Rene Blondlot: N-Rays

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**[rexresearch.com](../index.htm)**

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**Rene BLONDLOT**

**N-Rays**



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**[Robert Lageman: "New Light on Old Rays:
N Rays"](#lageman)**   
**[Rene Blondlot: N-Rays ~ A Collection of
Papers Communicated to the Academy of Sciences](#blondlot)**   
**[*Scientific American*: "Photographic
Records of the Action of N-Rays"](#sciam)**   
**[William Seabrook: The Great N-Ray
Delusion](#seabrook)**   
**[Goodle Search Results (Excerpts)](#google)**   
**[Marcel Ascoli: "Les Rayons N"Rene
Blondlot"](ascoli.htm)**

**See also: [Dobler/Telluric
Photography](../dobler/dobler.htm)**

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**Professor Rene P. Blondlot**   
![](1blondlot.jpg)

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***American Journal of Physics* 45 (3): 281-284 (March
1977)**

**"New Light on Old Rays: N Rays"**

**Robert T. Lagemann**   
(Dept of Physics and Astronomy, Vanderbilt Univ., Nashville
TN)

During the period 1903-1906, some 120 trained scientists
published almost 300 articles on the origins and characteristics
of a spurious radiation, the so-called N rays. Some new
explanations are advanced for the extensive false observations
and the deductions made from these observations. These are based
on visits to Nancy, France, where the purported discovery was
first announced and after which the rays were named, on an
interview with a former assistant who knew some of the
principals involved in the case, and on new archival
information. Some of the misleading statements in the subsequent
literature and oral history dealing with N rays are challenged,
and additional information is provided on the original
discoverer, Rene Blondlot.

**Introduction**

Mistakes in the process of discovery are not rare in physics
and the other sciences. Of special interest to physicists is the
purported discovery of N rays in 1903 by Rene Blondlot, a
professor of physics at the University of Nancy, France. Here is
a case unequalled in the number of scientists actively involved
and the number of notes and papers published in the scientific
journals of the day by scientists qualified by education,
academic appointment, and reputation to belong to the community
of scholars. Some 120 scientists published almost 300 articles
on the topic during the years 1903-1906, and the original
discoverer himself published 26 articles and a book (Ref. 1)
before halting, while one of his colleagues published no fewer
than 38 reports in the same three-year period -- all on "rays"
which have never since been observed. (Ref. 2)

American physicists, if aware of the case at all, are usually
limited in their knowledge to the information found in an
account by de Solla Price (Ref. 3) and a popular biography of
the American physicist, R.W. Wood (Ref. 4). It is the purpose of
this present contribution to correct certain notions about this
case presented in that biography, add information gathered
during visits to the city where the first experiments took
place, and provide a bibliography, especially of references not
likely to be discovered by or available to US physicists.

**The Purported Discoveries**

That such a protracted series of publications could be possible
is largely explicable from the fact that the observations of the
alleged radiation consisted of subjective viewing by the eye of
very feeble and often flickering sources of light, with all the
attendant physiological effects and difficulties of reproducing
observations (Ref. 5). In his first experiments (Ref. 6), when
he thought that x-ray tubes were a source of N rays, Blondlot
used as a detector a small spark whose increased brightness was
thought to be an indicator of the impinging rays (see Fig. 2).
Later he used a low-intensity gas flame as a detector. He soon
found additional sources of N rays besides x-ray tubes: (1) Auer
and Nernst burners (mixtures of rare earth salts heated to
incandescence), (2) the flame of an annular gas burner (but not
of a Bunsen burner), 3) a piece of sheet iron or silver heated
to dull redness, and (4) the Sun. He found new detectors: (1) a
small flame of gas flowing from a small orifice which in turn
could be better observed by noting its reflected image from a
ground-glass plate, and (2) surfaces covered with a properly
prepared deposit of calcium sulfide, which having first been
made phosphorescent by sunlight, revealed increased light
emission upon exposure to N rays. The difficulty of making
uniform films of calcium sulfide mixed with collodion and ether
led to confusion in observation, or so it was thought, and in
his book Blondlot provided instructions and a sheet bearing 25
calcium sulfide deposits for the reader to use to observe N
rays. To observe spectral lines of N rays, he packed a narrow
slit with calcium sulfide, moved the slit along in the region of
the expected dispersed beams, and when the sulfide showed
increased phosphorescence, a line was pronounced present.

Furthermore, he found that N rays could be stored in certain
materials. They traversed platinum 4 mm thick, but not rock slat
3 cm thick. They passed through dry cigarette paper but not
through the wetted paper. Certain solids in compression emitted
the rays, as when a walking cane was bent by the hand and held
near the eyes, and the "strengthening action" of the N rays on
the retina allowed faintly luminous objects to be seen better. A
file of tempered steel held near the eyes allowed surfaces and
contours to be seen, as for instance the dial of a clock in a
darkened room. He discovered N1 rays, which lessened the
luminosity of glowing sources. He found the "heavy emission",
which was claimed to consist of streams of minute particles
ejected form metals and certain liquids and to be subject to
gravitational attraction.

The Professor of Biophysics in the School of Medicine, Augustin
Charpentier, became especially adept at seeing the new rays. In
a single month (May 1904) he published seven papers on the
subject. He found that rabbits and frogs gave off the rays,
Tendons stretched by muscles gave no effects, but the biceps
muscle did. N rays increased the sensitivity of the human to
vision, smell, taste and hearing. Soon he found the rays from
living matter were somewhat different from the N rays, and he
called them "physiological rays". These latter could even be
transmitted along wires. Thus a small copper plate is fixed at
the end of a copper wire 90 cm long. At the other end is the
phosphorescent screen. When the human body is opposite the
plate, the screen lights up, indicating transmission of the
radiation through the wire. Both the physiological rays and the
N rays were transmitted in this way, he claimed. A long list of
medical and biological effects were chronicled in a book
published at the time (Ref. 7).

We have described only some of the findings claimed by two of
the many investigators. So extensive were the supposed
properties that G.F. Stradling required 59 pages simply to
enumerate or briefly describe the claims made over a 3-year
period (Ref. 8). At the same time there were those who could not
reproduce the effects claimed. Such recognized physicists as
Rayleigh, Langevin, Rubens, and Drude, for example, reported
failure. Indeed, within a month after Blondlots first
announcement, there appeared the first report of failure. But it
is the nature of scientific discovery for the world of science
to accept the findings of trained, reputable scientists until
such time as their results may be disproven by others. Blondlot
was a physicist of experience and accomplishment. At the time he
was one of 8 physicists who were corresponding members of the
French Academy of Science (Ref. 9). He had acquired a doctorate
in physics from the Sorbonne in 1881 with a thesis on electric
cells and laws of polarization of such cells. He had joined the
faculty at Nancy in 1882. In 1893 and again in 1899, he had
received prizes from the Academy (Ref. 10).

Similarly, P.M. Augustin Charpentier was a scientist of good
reputation, with the title of Professor of Medical Physics at
the University of Nancy. His thesis for the M.D. degree had been
entitled "Vision with the Different Parts of the Retina", and he
had numerous publications in the field of ophthalmology and
physiology, including one, for example, on "Physiological
Conditions Influencing Photometric Measurements" (Ref. 11).
Here, if anyone, was a man who should have been wary of the
mistakes that would be possible during observations of
flickering, low-intensity luminous sources. Many other observers
who reported success were as experienced as Blondlot and
Charpentier.

**Woods Exposure**

The purported finding of a new radiation had, of course, been
discussed at meetings of physics societies. There the reaction
was almost uniformly one of disbelief, based often on futile
attempts made sometimes with specific instructions furnished by
Blondlot himself. It was while attending such a meeting in
Europe, after having failed to obtain positive results in his
own laboratory at John Hopkins, that the American physicist R.
W. Wood decided to visit Nancy during the summer of 1904 and ask
the discoverer to show him the experiments. The story of his
visit is told in various places (Ref. 12). It suffices to say
here that during one demonstration, while Blondlot was finding
spectral lines in a refracted beam of N rays, he was doing so
with an essential part of the apparatus missing. At the
beginning of the observations and in the darkness, Wood had
placed the necessary prism in his pocket and then replaced it
before the room lights were turned back on. Woods report
signaled the end of the N-ray affair.

**Some Explanations**

When it became evident that some physicists could not observe
the rays, Blondlot invited a few to visit his laboratory, and in
the appendix of his book he made suggestions for successful
observations. These instructions, themselves not easily
followed, provided insufficient aid in observing a phenomenon
which did not in fact exist. Hoping the provide objective,
convincing evidence, Blondlot took photographs (see Fig. 3) of
light sources both when exposed and not exposed to the action of
N rays and found those exposed to N rays to have produced a
darker negative. But when the nonreality of the rays became
apparent, the photographic evidence was explained by his
detractors as caused by nonuniform photographic emulsions and
poorly controlled exposure time and development. Pierret (Ref.
13) implies that the exposure and development of the plates for
equal conditions were not performed by Blondlot but were left to
the assistants. In brief, the difficulties introduced by
subjective observation of low-intensity sources, whose energy
output varied with time, led to spurious results. But this was
compounded by the failure of the observers to perform what today
we call the controlled experiment, and to apply the classical
method of difference and the method of agreement (Ref. 14). Even
such psychological factors as can be grouped under
suggestibility and hypnosis, and such motivational factors as
national pride and the quest for prestige, could have been
eliminated or their importance reduced if reproducibility of
results and control of the conditions of comparison had been
better effected.

Recognition of the inherent difficulty of observation does not
alone explain the widespread observations. Deliberate fraud can
be ruled out, both because so many different scientists were
involved and because they had nothing to gain from reporting
findings which could be subjected to confirmation by others.
What of deceit on the part of Blondlots colleagues and
assistants? The two other physicists at Nancy themselves made
announcements of N ray discoveries and could not, therefore, be
thought to be deceiving or encouraging Blondlot (Ref. 15). And
as for his chief assistant, according to Wood, and Pierret, he
was not learned enough in science to perpetrate such a deception
(Ref. 16). At any rate Blondlot retained his services afterward,
and certainly any such deception cannot explain why others in
distant laboratories "saw" the effects. For explanations of the
involvement of so many persons one might profitably turn to the
phenomena of suggestion, hypnosis, and mass hysteria. Such a
psychological study waits to be done.

**Some New Aspects**

A few new aspects to the case have, however, been uncovered by
the present writer during visits to the city of Nancy that shed
some light on the reasons for the announcement of the original
observations by Blondlot. In his book, Seabrook states that
"only Frenchmen could observe the phenomena", a minor
exaggeration he must have heard from the flamboyant Wood (Ref.
17). But for the record it should be mentioned that J.S. Hooker
(Ref. 18), an Englishman, and F.E. Hackett (Ref. 19), a student
at the Royal University of Ireland, reported that they had
observed the rays. And another non-Frenchman who observed the
rays was Leslie Miller, an instrument-maker of London, who so
believed in their reality, or at least in the commercial
exploitation of the rays, that he made apparatus for observing
them which he sold for L. 1,1,0 (Ref. 20). Seabrook is wide of
the mark, on the other hand, when he writes: "The tragic
exposure eventually led to Blondlots madness and death".
Actually, Blondlot continued in his post of Professor of Physics
for six years after Woods disclosure. He retired in 1910
(Ref.21) at the age of 61, before the usual age of retirement.
He lived for 20 years in retirement, until his death in 1930 at
the age of 81 (Ref. 22). During that period he held the title
Professor Honoraires (i.e., emeritus) and continued to live in
his large home at 16-18 Quai Claude le Lorrain. He continued to
have associations with others at the University, as when for
example, in 1909, on the occasion of the unveiling of a monument
of his friend, Ernest Bichat, Blondlot made one of the speeches.
In 1923, a third edition of his book on thermodynamics appeared,
and in November 1927, he wrote a new preface for a third edition
of his textbook on electricity (Ref. 23). Certainly his long
will, frequently revised to accommodate changing conditions,
which was duly accepted and probated upon his death, is one
prepared by a sane man (Ref. 24).

Nor is there any evidence that he committed suicide, as is
sometimes inferred by those who read Seabrook. Blondlot lived
some 26 years after Woods exposure. Had he taken his own life,
he probably could not have been buried in a Catholic cemetery
with the full rites of the Church, as was indeed the case
according to newspaper accounts. Cemetery records show he is
buried in the Cimetiere de Preville, the central one of the
city.

Modern scientists at the University of Nancy know little or
nothing about the history of N rays, and those who do are
usually reluctant to speak of the mater. Two, however, freely
expressed themselves on the impressions they had acquired from
colleagues who had been alive at the time or who in turn had
known such. One I interviewed was Josef Bolfa, Prof. of
Mineralogy and Crystallography, who has long had an interest in
the history of the University. His view is that a prominent, but
little recognized factor in the discovery was the national and
regional pride of the Nancy professors, who were aware of the
recent discovery of the cathode rays, x rays, and canal rays by
their counterparts in other countries wanted to bring fame to
France and exploited the original observations without due
regard to firm evidence. Moreover, he said, Nancy has for a long
time been a garrison city in the French military system.
Repeatedly he used the words, "Cest une erreur".

E. Pierret, with whom I talked, probably has more direct
knowledge of the case than anyone else. Retired now from his
post of chief assistant in the Department of Physics, he told me
he had known the assistants who worked with Blondlot and
Charpentier, and he showed me the very prisms and lenses (Ref.
25) used by Blondlot in his investigations. He had talked with
Blondlot in 1926, at which time Blondlot did not appear to have
lost his intellectual powers. Blondlot, he said, continued to
believe in the existence of N ryas after he stopped his active
study of them in 1906, and continued to teach for a few years
afterward. He never blamed his former assistant for any
deception (Ref, 26), but, at the same time, Pierret noted, in
the days prior to the N rays studies, one of the assistants had
received from Blondlot part of the prize money won by Blondlot
for discoveries made in the laboratory and doubtless welcomed
the prospect of new awards for the finding of this new,
extraordinary radiation, a prospect which might have influenced
his observations. It was the custom of the day for an
experimentalist to give but general instructions to an
assistant, who would be expected to build or assemble apparatus
and make many of the observations. This was Blondlots custom.
Pierret felt also that the assistant responded to the
suggestions and authority of the professor and sawmore than the
evidence warranted.

A useful summary of the case, entitled "A la Poursuite des
Rayons N", was published in 1965 by C. Gelain and H. Geoffrey,
who include photographs of some of the prisms and lesnes used by
Blondlot as well as a photograph of Blondlots laboratory of
about 1900 (Ref. 27). Another interesting summary is that of
Jean Rosmorduc (Ref. 28). A brief treatment of the case is given
by Jean Rostand (Ref. 29), while some of the psychological
aspects have been discussed by Y. Galifret (Ref. 30).

**Acknowledgments**

It is a pleasure to express my thanks to Mr. Emile Pierret,
Prof. Joseph Bolfa, and, especially, Prof. Jacques Touret -- all
of the University of Nancy -- for much assistance and fruitful
discussions. Part of the study was supported by a grant from the
Vanderbilt University Research Council.

**References**

(1) R. Blondlot, N Rays: *[A Collection
of Papers Communicated to the Academy of Sciences](#blondlot)*;
Transl. J. Garcin; Longman, Green, London, 1905. French edition,
1904, by Gauthier-Villars, Paris.

(2) See G.F. Stradling, *J. Franklin Inst.* 164: 57-64
(1907); *ibid*., 164: 113-130 (1907); *ibid*., 164:
177-199 (1907). Written at the close of the period of active
interest in the rays, this series of three articles gives the
most comprehensive recital of the alleged discoveries. Stradling
lists 278 references to original articles, resumes, and
editorial comment. In addition, he states, there were summaries
in 15 other professional and popular magazines.

(3) D. J. de Solla Price, *Science Since Babylon* (Yale
Univ. Press, New Haven CT, 1975), pp. 153-160.

(4) W. Seabrook, *Doctor Wood* (Harcourt, Brace and
World, NY, 1941), pp. 233-239.

(5) The speculations, false starts, spurious results, and
confusion attendant upon the study of N rays are similar to
those associated with the early observations of radioactivity by
Henri Becquerel and others, but of course the N rays were
spurious, while the rays of radioactivity were not. See L.
Badash, *Amer. J. Physics* 33: 128 (1965).

(6) R. Blondlot, *C.R. Acad. Sci.* 136: 284 (1903); *ibid*.,
136:
735 (1903); *ibid*., 136: 1120 (1903); *ibid.*, 137:
684 (1903).

(7) H. Bordier, *Les Rayons N et les Rayons N1; Les
Actualites Medicales* (Baillere, Paris, 1905).

(8) G.F. Stradling, Ref. 2.

(9) There were also 6 regular members who were physicists, and
4 foreign members: Rayleigh, Hittorf, van der Waals, and
Michelson.

(10) Rene Prosper Blondlot was born on 3 July 1849 in Nancy,
France, and died in the same city on 24 November 1930. He was
the son of Nicolas Blondlot (b. 1808), who held an M.D. degree
and was for a long time Prof. of Toxicology in the Faculty of
Medicine. In 1893, the French Acad. Awarded him the Gaston
Plante prize, in 1899 the LaCaze prize, and in 1904 (with the N
ray controversy at its height), the Le Conte prize. He had been
elected a correspondent of the Academy in 1894, taking the place
of Helmholtz.

(11) A. Charpentier, *C.R. Acad. Sci.* 103: 130 (1886)

(12) W. Seabrook, Ref.4; *Nature* 70: 530 (1904); *Electr.
Review* 45: 630 (1904); *Phys. Zeitschr*. 5: 789
(1904); *Rev. Sci.*. 2: 536 (1904).

(13) E. Pierret, *Bull. Acad. Soc. Lorraines Sci*. 7: 240
(1968).

(14) These methods are much used by physicists who, on the
whole, are often not aware of their formalization by J.S. Mill
and others. However, much as Mills canons have been criticized,
they would have been useful guides to N ray students.

(15) In 1905, at the height of the N ray controversy, there
were two professors of physics at Nancy, Rene Blondlot and
Ernest Bichat. This unusual arrangement (of more than one) was
brought about by Bichats added duties as Doyen (Dean) of the
Faculty of Sciences. Bichat died in 1905; a life-size statue of
him presently stands before a science building of the
University. A third scientifically trained member of the
department was Camille Gutton, who at the time was Maitre de
Conferences (in charge of the teaching duties of the
department). Upon Blondlots retirement, Gutton was made Prof.
of Physics, and upon Bichats death he was made Dean, upon the
condition that he not persist in expressing a belief in the
reality of N rays.

(16) During my interview with him, Pierret declined to reveal
the name of Blondlots assistant.

(17) Seabrook also has Blondlot announcing his discovery "in
the late autumn of 1903", whereas in his paper of 23 March 1903,
*C.R. Acad. Sci*. 136: 735 (1903), the discoverer used the
words "n-rays", which were later changed to "N-rays".

(18) J.S. Hooker, *Lancet* 1:686 (1904); *ibid.*,
2: 1380 (1904).

(19) F.E. Hackett, *Sci. Trans. Roy. Soc. Dublin* 8: 127
(1904); *Nature* 70: 167 (1904); *ibid*., 70: 583
(1904).

(20) L. Miller, *Electrician* (Lond.) 52: 788 (1904), an
advertisement; *Lancet* 1: 610 (1904); *ibid*., 1:
831 (1904); *ibid*., 1: 1150 (1904).

(21) Pierret, in Ref. 13, states that in November 1909,
Blondlot chose to retire from his University post. "It has been
said", writes Pierret, "that he [resigned] at the instance of a
committee of inquiry". Probably the retirement became effective
about September 1910.

(22) See *Cest Republicain* (daily newspaper of Nancy)
for 27 Novemeber 1930. Also *Biographique des Membres et
Correspondants de LAcademie des Sciences*;
(Gauthier-Villars, Paris, 1954).

(23) E. Bichat and R. Blondlot, *Introduction a lEtude de
lElectricite Statique at de Magnetisme* (Gauthier-Villars,
Paris, 1927).

(24) The will is to be found in Archives
Departmentales/Archives Historiques/Centre de Documentation
Administrative/Service Educatif in Nancy. Blondlot never married
and at his death had no close living relatives. A portion of his
estate was divided among servants and friends, but the largest
part, his house and garden of about 1.65 acres, was given to the
city of Nancy to serve, in the case of the garden, as a place of
rest for the townspeople and, in the case of the house, as a
place where young people could come to obtain advice about job
and educational opportunities. They are in use today for the
purposes intended. The entire estate was valued at over one
million francs. As a consequence of his beneficence, the city
bestowed on him a special title. The park adjacent to his former
home bears the inscription Pac Blondlot above the entrance. A
street in the city is also named after him.

(25) The writer saw and handled these items. There were 5
prisms which appeared to be made of aluminum, silver, clear
(transparent) quartz, smoky quartz, and wood. The height of each
was about 6 cm. The faces of each approximated squares. One
prism (Ag?) of which I drew the base by drawing a pencil along
the edges as I held it on a piece of paper, had a prism angle of
about 29\*. The others appeared to the eye to be somewhat
smaller, all with a prism angle of perhaps 22\*. A metal
plano-convex lens of aluminum measured 7 cm in diameter. I
estimated the curvature of its convex face to be about 30 cm
radius. Pierret did not show me, if indeed they were in his
possession, the 60\* and 90\* aluminum prisms used by Blondlot.
Pierret became an assistant in the department about 1928. One
day while taking an inventory of the contents of a laboratory,
he came upon the materials used in the N-ray work. Another
assistant, said Pierret, warned him not to touch them or to
speak of the subject to the professor in charge. In 1962, when
he retired from the post of Maitre de Conferences, the materials
came into his possession.

(26) This belief is also expressed in Pierrets article on the
subject. See Ref. 13, p. 254.

(27) C. Gelain and H. Geoffrey, *Ing. Ind. Chim*. 41: 7
(1965).

(28) J. Rosmorduc, *Rev. Hist. Sci. Leurs Appl.* 25: 13
(1972).

(29) J. Rostand, E*rror and Deception in Science* (Basic,
NY, 1960).

(30) Y. Galifret, *Courr. Ration.* 9: 191 (1963).

---



**"N-Rays ~ A Collection of Papers
Communicated to the Academy of Sciences**

**With Additional Notes and Instructions for the
Construction of Phosphorescent Screens**   
  
**by**

**Rene Prosper Blondlot**

Professor, University of Nancy

Translated by J. Garcin   
Longmans, Green and Co.( London, New York and Bombay ) 1905

**(a) Preliminary Notice**

The present volume contains the memoirs on the subject of "N"
rays, communicated to the Academy of Sciences by Prof. R.
Blondlot. The papers have been reprinted exactly as they were
originally published in the Comptes Rendus of the Academy. The
notes at the end were added later, with the object of throwing
light on certain points which were obscure at the time the
papers were communicated to the Academy.

The title of the first memoir in this collection, "On the
Polarization of X-Rays", will hardly cause astonishment when it
is realized that the study of the X rays led the author to
recognize the existence of radiations of a totally different
character. To these he gave the name of "N" rays. Before the
distinction of these two kinds of radiation was made, some
confusion was bound to arise between the phenomena appertaining
to each. In particular, the preliminary researches which the
author had made on the velocity of propagation of X rays apply
in reality not to X rays, but to N rays. He had found that the
velocity of propagation was the same as that of Hertzian waves,
and consequently of light. Since the properties of N rays, taken
in their entirety, do not leave any doubt that these rays are a
variety of light, this determination of their velocity is
nothing more than a verification of an assured fact.
Nevertheless, this verification seemed not altogether
superfluous; it proves at least that the experiments have been
carried out with care.

**Table of Contents**

**[(1)  On the Polarization of X Rays](#1)**
  
**[(2)  On a New Species of Light](#2)**   
**[(3)  On the Existence, in the Radiation
Emitted by an Auer Burner, of Rays Transmissible Through
Metals, Wood, etc.](#3)**   
**[(4)  On New Sources of Radiations
Transmissible  Through Metals, Wood, etc., and on New
Actions Produced by These Radiations](#4)**   
**[(5)  On the Existence of Solar Radiations
Capable of Traversing Metals, Wood, etc.](#5)**   
**[(6)  On a New Action Produced by N Rays,
and on Certain Facts Connected with These Radiations](#6)**
  
**[(7)  On New Actions Produced by N Rays;
Generalization of Phenomena Already Observed](#7)**   
**[(8)  On the Storing of N Rays by Certain
Bodies](#8)**   
**[(9)  On the Strengthening Action of a Beam
of Light on the Eyes, When the Beam is Accompanied by N Rays](#9)**
  
**[(10)  On the Property of Emitting N Rays
Conferred on Certain Bodies by Compression, and on the
Spontaneous and Indefinite Emission of N Rays by Hardened
Steel, Unannealed Glass, and Other Bodies in a State of
Strained Molecular Equilibrium](#10)**   
**[(11)  On the Dispersion of N Rays and on
Their Wave Length](#11)**   
**[(12)  On the Photographic Registering of
the Action Produced by N Rays on a Small Electric Spark](#12)**
  
**[(13)  On a New Species of N Rays](#13)**   
**[(14)  On Peculiarities Presented by the
Action Which N Rays Exercise upon a Dimly Lighted Surface](#14)**
  
**[(15)  On the Comparative Action of Heat
and N Rays on Phosphorescence](#15)**   
**[(16)  Complementary Notes](#16)**   
**[(17)  Instructions for Making
Phosphorescent Screens](#17)**   
**[(18)  How the Action of N Rays Ought to be
Observed](#18)**

**(1) On the Polarization of X Rays (Feb. 2, 1903)**

Hitherto the attempts made to polarize X rays have remained
fruitless. I asked myself whether X rays emitted by a focus tube
are not polarized as soon as emitted. I was led to put to myself
this question by considering that the conditions of asymmetry
which should exist for the polarization of such rays are in this
case exactly satisfied. For each ray is generated from a cathode
ray, and the two rays define a plane; thus, through each ray
emitted by the tube a plane passes, in which, or normally to
which, the ray may well have special properties, this being, in
fact, an asymmetry characteristic of polarization. Now, if this
polarization exists, how can the fact be ascertained? It struck
me that a small spark, such as I used in my researches on the
velocity of propagation of X rays, might perhaps in this case
play a part of analyzer, inasmuch as the properties of a spark
may be different in the direction of its length, which is also
that of the electric forces producing it, and in directions
normal to its length. Starting from this, I arranged an
apparatus as shown in the accompanying diagram, so as to obtain
a small spark during the emission of X rays.

![](0blo1.gif)

A focus tube is connected to an induction coil by wires BH,
BH, covered with gutta percha (Fig.1). Two other wires, also
covered with gutta percha, AIc and AIc, terminate at A and A
in two loops, which surround BH and BH respectively; a bit of
glass tubing, not shown in the figure, keeps each loop separate
from the wire which it surrounds. The wires AI, AI are then
twisted together, and their sharply pointed end, c and c, are
fixed opposite each other, at a very small distance, adjustable
at will, so as to form a small spark gap. By virtue of this
disposition, the electrostatic influence exercised by the wires
BH and BH on the loops A and A produces at each break of the
current in the coil a small spark at the gap cc, at the same
time as X rays are being emitted by the tube. Owing to the
flexibility of wires, AIc, AIc, the straight line cc, along
which the spark occurs, can be set in any direction we please. A
sheet of aluminum foil, 40 cm square, is interposed between the
tube and the spark, so as to prevent any direct influence of the
electrodes of the tube on cc.

In order to define easily the relative positions of the tube
and the spark cc, take three rectangular axes, of which one,
Oz, is vertical.

Fix the focus tube so that its length, and consequently, the
pencil of cathode rays, coincides with OY, the anticathode being
placed near the origin, and sending X rays in the positive
direction of OX.

Place the gap cc at a point on the positive side of OX, so
that its direction is parallel to OY. The spark being properly
regulated one observes that the X rays act upon it in such a way
as to increase its luminosity, for the interposition of a sheet
of lead or glass manifestly diminishes the brightness.

Now, without altering the position of the gap, turn it so that
it comes parallel to OZ, i.e., normal to the cathode rays. The
influence of the X rays on the spark is then seen to disappear,
and the interposition of a lead or glass plate causes no change
in its brightness.

X rays have therefore a plane of action, which is the one
passing through each X ray and the cathode ray which gives rise
to it. If the direction given to the spark gap is intermediate
between the two above mentioned, the action is seen to diminish
from the horizontal position to the vertical.

The following is another experiment, still more striking: if
the spark is made to turn about OX, parallel to plane YOZ, the
spark is seen to pass from a maximum brightness when horizontal
to a minimum when vertical. These variation of brightness are
similar to those observed when a pencil of polarized rays
traverse a rotating Nicols prism, the small spark playing the
part of analyzer. The pencil of X rays presents the same
asymmetry as a pencil of polarized light. According to Newtons
definition, it has sides differing from each other; in other
words, it is polarized in the complete sense of the term.

The phenomenon is easy to observe when the spark is well
regulated; this means that the spark must be very small and
faint.

If the focus tube is made to turn about its axis, which is
parallel to the cathode rays, the observed phenomena do not
change, so long as X rays reach the gap. The plane of action is
thus independent of the orientation of the anticathode, being
always in the plane passing through the X rays and the
generating cathodic rays.

The spark being kept in this plane, and turned round from the
position in which it is at right angles to the X rays to that in
which it is parallel to them, we observe that the effect of the
X rays on the brightness of the spark is a maximum in the first
position, and diminishes to nothing in the second.

Now, an X ray and its generating cathodic ray only determine a
plane when their directions are different. Again, amongst the
emitted X rays, some are in a direction very nearly the same as
that of the cathode rays, being those which graze the cathode.
One should expect these to be every incompletely polarized; and,
indeed the small spark enabled me to confirm this.

I noted several important facts, which, however, I will merely
allude to in the present paper. Quartz and lump-sugar rotate the
plane of polarization of X rays in the same sense as that of
light. I obtained rotations of 40 degrees.

Secondary rays, styled "S" rays, are also polarized. Active
substances rotate the plane of polarization of these rays in a
sense contrary to that of light. I observed rotations of 18
degrees (Note 2).

It is extremely likely that magnetic rotation also exists for X
rays as well as for S rays. Once can also surmise hat the
properties of these rays, with reference to polarization, extend
to tertiary rays, etc. I intend shortly to publish the results
at which I have arrived concerning these different points.

**(2) On a New Species of Light (March 23, 1903)**

The radiations emitted by a focus tube are filtered through a
sheet of aluminum foil or a screen of black paper, in order to
eliminate the luminous rays which might accompany them. While
studying these radiations by means of their action on a small
spark, I discovered that they are plane-polarized as soon as
emitted. I further proved that when these radiations traverse a
plate of quartz in a direction at right angles to its axis, or a
lump of sugar, their plane of action undergoes a rotation just
like the plane of polarization of a pencil of light.

I then asked myself if a rotation could also be obtained by
passing the radiations of the focus through a pile of Reusch
mica sheets. I observed, in fact, a rotation of from 25 deg to 30 deg
in the same direction as that of polarized light. This action of
a pile of micas made me at once infer that a single sheet of
mica must act, and that this action must be depolarization, or,
rather, the production of elliptic polarization; this is indeed
what occurs. The interposition of a sheet of mica, set so that
its axis makes an angle of 45 deg with the pane of action of the
radiations emitted by the tube, destroys their rectilinear
polarization, for their action on a small spark remains sensibly
the same, whatever be the direction of the spark gap. If a
second sheet of mica is interposed, identical with the first, so
that the axes of the two sheets are perpendicular to each other,
rectilinear polarization is reestablished. This result can also
be obtained by the use of a Babinets compensator. Consequently
we are dealing with elliptic polarization.

Now, if the sheet of mica changes rectilinear into elliptic
polarization, such a sheet must be doubly refractive for the
radiations thus formed. But if double refraction exists, a
fortiori simple refraction must exist; and I was thus led to
examine whether, in spite of the fruitless attempts to discover
the refraction of X rays, I could not obtain a deviation by a
prism. I then arranged the following experiment: a focus tube
sends through an aluminum screen a pencil of rays, limited by
two vertical slits cut in two parallel sheets of lead, 3 mm
thick. The small spark is placed on one side of the pencil at
such a distance that it cannot be reached, even by the penumbra;
this is ascertained by proving that the interposition of a sheet
of lead causes no diminution of its brightness. Now let us
interpose in the pencil an equilateral quartz prism, with
refractive edge on the side away from the spark. If the prism is
properly set, the spark becomes much more brilliant; when the
prism is removed, the spark reverts to its former faintness.
This phenomenon is certainly due to refraction, for if the
setting of the prism is altered, or if the prism is replaced by
a plate of quartz, no effect is observed. The experiment may
also be carried out in a different manner: the pencil is first
made to impinge directly on the spark, then it is deviated by
means of the prism, and the brightness of the spark wanes. If,
now, the spark is moved laterally towards the base of the prism,
it recovers its previous brightness, proving that the rays in
question have been deviated in the same sense as rays of light.

 Refraction being thus proved, I at once sought to
concentrate the rays by means of a quartz lens. The experiment
is unattended with difficulty. An image of the anticathode is
obtained, extremely well-defined as to size and distance by a
heightened glow of the small spark.

The existence of refraction rendered that of regular reflection
extremely probable; as a matter of fact, regular reflection does
take place. By means of a quartz lens, or a lens formed by a
very thin horn envelope filled with turpentine, I produce a
conjugate focus of the anticathode; then I intercept the
emerging pencil by a sheet of polished glass, placed obliquely;
I then obtain a focus exactly symmetrical, in respect to the
plane of reflection, with the one which existed before the glass
was interposed. With a plate of ground glass there is no regular
reflection, but diffusion is observed.

If one half of a lamina of mica is roughened, the polished half
lets pass the radiations, and the other half stops them (note 3)

This allows of the repetition of the refraction experiments
under much more precise conditions, by the use of Newtons
arrangement for obtaining a pure spectrum.

From all that precedes, the fact results that the rays which I
have thus studies are not Roentgen rays, since these undergo
neither refraction nor reflection. In fact, the little spark
reveals a new species of radiations emitted by the focus tube,
which traverse aluminum, black paper, wood, etc. These are
plane-polarized from the moment of their emission, are
susceptible of rotary and elliptic polarization, are refracted,
reflected and diffused, but produce neither fluorescence nor
photographic action.

I had expected to find that amongst these rays some existed
whose refractive index for quartz is about 2; but probably quite
a spectrum of such rays exists, for in the refraction
experiments with a prism, the deviated pencil appears to cover a
broad angle. The study of this dispersion remains to be pursued,
as well as that of the wavelengths of the rays.

By progressively diminishing the intensity of the current
actuating the induction coil, one still gets these new rays,
even when the tube no longer produces any fluorescence, and is
itself absolutely invisible in the dark. They are fainter,
however, in this case. They can also be produced continuously by
means of an electric machine giving a spark a few millimeters in
length.

At first I had attributed to Roentgen rays the polarization
which in reality belongs to the new rays, a confusion which it
was impossible to avoid before having observed the refraction,
and it was only after making this observation that I could with
certainty conclude that I was not dealing with Roentgen rays,
but with a new species of light.

It is interesting to collate these remarks with the view
expressed by M. Henri Cecquerel, that in certain of his
experiments "manifestations identical with those giving
refraction and total reflection of light may have been produced
by luminous rays which had traversed aluminum" (see Comptes
Rendus, t. xxxii, March 25, 1901, p. 739).

**(3)  On the Existence, in the Rays Emitted by an Auer
Burner, of Radiations which Traverse Metals, Wood, etc. (May
11, 1903)**

A focus tube emits, as I have already proved, certain
radiations susceptible of traversing metals, black paper, wood,
etc. Amongst these, there are some for which the index of
refraction of quartz is nearly 2. On the other hand, the index
for quartz of the rays remaining from rock-salt, discovered by
Prof. Rubens, is 218. This similarity of indices led me to
think that the radiations observed in the emission of a focus
tube would very likely be near neighbors of the rays discovered
by Rubens, and that, consequently, they would be met with in the
radiation emitted by an Auer burner, which is the source of such
rays. I accordingly made the following experiment: an Auer
burner is enclosed in a kind of lantern of sheet-iron,
completely closed on all sides, with the exception of openings
for the passage of air and combustion gases, which are so
arranged that no light escapes; a rectangular orifice, 4 cm wide
and 6.5 cm high, cut in the iron at the same height as the
incandescent mantle, so that the emerging luminous pencil is
directed on the aluminum sheet. Outside the lantern, and in
front of this sheet, a double-convex quartz lens is placed,
having 12 cm focal length for yellow light, behind which is a
spark gap of the kind already described, giving very small
sparks. The spark is produced by a by a small induction coil,
provided with a rotating make and break device, which works with
perfect regularity.

The distance *p* of the lens from the slit being 26.5 cm,
one notes, by help of the spark, the existence of a focus of
very great sharpness at a distance, *p*, of about 13.9
cm. For at this point the spark exhibits a notably greater glow
than at the neighboring points, whether in front or behind,
above or below, to the right or to the left. The distance of
this focus from the lens can be determined within 3 or 4 mm. The
interposition of a sheet of lead or glass 4 mm thick causes this
action to disappear. By varying the value of *p*, other
values of *p* are obtained, and substituting these values
in the lens formula, the number 2.93 is obtained for the
refractive index, being the mean value derived from a series of
determinations as concordant as the precision of such
observations could entitle one to expect. Similar experiments,
made with another quartz lens, having a focal length of 33 cm
for yellow light, gave for the index the value 2.942.

While pursuing these experiments, I ascertained the existence
of three other species of radiations, for which the index of
quartz has values 2.62, 2.436, and 2.29 respectively. These
indices are all greater than 2, which explains the following
fact: if in the path of the rays emerging from the lens a quartz
prism of 30 degrees refractive angle is placed, in such a way as
to receive these rays in a direction sensibly normal to one of
the refracting faces, no refracted pencil is obtained.

The radiations from an Auer burner, transmitted through an
aluminum sheet, are reflected by a polished plate of glass in
conformity with the laws of regular reflection, and are diffused
by a plate of ground glass.

These radiations traverse all the substances whose transparency
I tested, with the exception of rock-salt 3 mm thick (note 4),
platinum 4 mm thick, and water. A slip of cigarette paper, which
is completely transparent when dry, becomes absolutely opaque
when wetted with water. Figs. 2 and 3 are reproductions of the
impression made in four seconds on a sensitive plate, without
any photographic apparatus, before and after wetting the sheet
of paper interposed between the lens and the spark. The
photoengraving, produced from a paper print, shows in the first
case the spark is notably brighter.

These photographic prints are produced by the spark influenced
by the rays, and not by the rays themselves, these latter
producing no appreciable photographic effect after an hours
exposure.

Amongst the bodies which are traversed, I may mention tin foil,
sheets of copper and brass 0.2 mm thick, a sheet of aluminum 0.4
mm thick, a steel lamina 0.05 mm thick, a silver leaf 0.1 mm
thick, a paper booklet, containing 21 gold leaves, a glass sheet
0.1 mm thick, a sheet of mica of 0.15 mm, a plate of Iceland
spar of 0.4 mm, a block of paraffin of 1 cm, a beech board 1 cm,
a plate of ebonite of 1 mm, etc. Fluorspar is but slightly
transparent with a thickness of 5 mm, similarly sulfur 2 mm
thick, and glass 1 mm thick. These results I give only as a
first indication, for when they were obtained, the co-existence
of four different species of radiations, which may have very
different properties, was not taken into account (note 5).

It will be highly interesting to investigate whether other
sources, and in particular the sun, do not emit analogous
radiations to those we are dealing with in the present
communication, and also whether the latter produces any
calorific action (note 6).

Now, ought these radiations in reality to be considered as akin
to the large wave length radiations discovered by Prof. Rubens?
Their common origin in the emission of an Auer burner is
favorable to such a view, as is also the opacity of rock-salt
and of water. But on the other hand, for Auer rays, the
transparency of metals and other substances opaque to Rubens
rays constitute an apparently radical difference between the two
sorts of radiations (note 7).

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**(4)  On New Sources of Radiations Capable of Traversing
Metals, Wood, etc., and on New Actions Produced by These
Radiations (May 25, 1903)**

While investigating whether radiations analogous to those whose
existence I mentioned in the emission of an Auer burner are not
to be met also in other sources of light and heat, I established
the following facts: the flame of an annular gas-burner emits
such radiations; the chimney, however, should be removed, on
account of the absorption of the rays by glass. A Bunsen burner
scarcely produces any. A piece of sheet-iron or silver, heated
to dull redness by a Bunsen burner, placed behind them, gives
off rays at about the same rate as an Auer burner.

A plate of polished silver was arranged so that its plane made
an angle of 45 deg with the horizontal plane. This plate having
been heated to cherry-red by a Bunsen burner, its upper face
emitted rays analogous to those of an Auer burner. A horizontal
pencil of these rays, after traversing two sheets of aluminum of
0.3 mm total thickness, sheets of black paper, etc., was
concentrated by a quartz lens; with the aid of the small spark,
the existence of four focal regions was ascertained. I further
found that the action on the spark was much more pronounced when
the spark was arranged vertically -- that is, in the plane of
emission -- than when it was normal to this plane. The new
radiations emitted by the polished plate are therefore
polarized, as are the light and heat emitted at the same time.
The silver plate having been covered with lampblack, the
intensity of the emission increased, but the polarization
disappeared.

The foregoing leads one to think that the emission of
radiations susceptible of traversing metals, etc., is an
extremely general phenomenon. First observed in the emission of
a focus tube, it was also met in that of ordinary sources of
light and heat. For shortness, I will henceforth designate these
rays by the name of "N" rays.

[ From the name of the town of Nancy, these researches having
been made at Nancy University. ]

I would draw attention to the fact that these N rays comprise a
very large variety of radiations; for while those which issue
from an Auer burner have refractive indices greater than 2,
there are others, amongst those emitted by a Crookes tube, whose
index is inferior to 1.52, for if a pencil of these rays is made
to impinge on an equilateral quartz prism, parallel to the edges
and normal to one of the faces, an emerging pencil is obtained
which is very much spread out.

Up to this time the only means of detecting the presence of N
rays was by their action on a small spark. I asked myself if the
spark should in this case be considered as an electric
phenomenon, or only as producing incandescence like a small
gaseous mass. If this latter supposition were correct, the spark
could be replaced by a flame. I then produced a quite small
flame of gas at the extremity of a metal tube having a very
small orifice. This flame was entirely blue. I ascertained that
the flame could be used to reveal the presence of N rays just
like the spark; for when it receives these rays, it becomes
whiter and brighter in just the same way. Its variations in glow
allowed of four foci being found in a pencil which had passed
through a quartz lens; these foci are the same as those detected
with the small spark. The small flame behaves therefore, in
regard to N rays, just like the spark, save that it does not
allow of the observation of polarization phenomena.

In order to study more easily the variations in glow, whether
of flame or spark, I examine them through a plate of ground
glass, about 25 or 30 mm distant. In this way one obtains,
instead of a very small, brilliant point, a luminous patch of
about 2 cm diameter, of much less luminosity, whose variations
can be far better appreciated by the eye.

The action of an incandescent body on a flame, or that of a
flame on another flame, is certainly a common phenomenon. If it
has remained unnoticed up to the present, it is because the
light of the source prevented the observation of the variations
in glow of the receiving flame.

Quite recently I observed another effect of the N rays. It is
true that these rays are unable to excite phosphorescence in
bodies which can acquire this property under the action of
light, but when such a body --- calcium sulfide, for example ---
has previously been rendered phosphorescent by exposure to
sunlight, if it is then exposed to N rays --- for instance, to
one of the foci produced by a quartz lens --- the phosphorescent
glow is observed to increase in a very marked fashion; neither
the production nor the cessation of this effect appear to be
absolutely instantaneous. Of all the actions producing N rays,
this is the one which is most easily observed. The experiment is
an easy one to set up and to repeat. This property of N rays is
analogous to that of the red and infrared rays discovered by
Edmond Becquerel. It is also analogous to the action of heat on
phosphorus. Nevertheless, I have not noticed as yet an increased
rate of exhaustion of the phosphorescent capacity under the
action of N rays.

The kinship of N rays with known radiations of large wavelength
seems a certain fact. As, on the other hand, the property
possessed by these rays of traversing metals differentiates them
from all known radiations, it is very probable that they are
comprised in the five octaves of the series of radiations,
hitherto unexplored, between the Rubens rays and electromagnetic
oscillations of very small wavelength. This is what I propose to
verify.

**(5)  On the Existence of Solar Radiations Capable of
Traversing Metals, Wood, etc. (June 15, 1903)**

I have recently proved that the majority of artificial sources
of light and heat emit radiations which are able to traverse
metals and a great number of bodies, opaque in regard to the
spectral radiations hitherto known. It was desirable to
ascertain whether radiations analogous to the former --- which,
for brevity, I call N rays --- are also emitted by the sun.

As I have shown, N rays act on phosphorescent substances by
heightening or stimulating the pre-existing phosphorescence, an
action similar to that of red and infrared rays discovered by
Edmond Becquerel. I utilized this phenomenon to find out whether
the sun sends us N rays.

A completely enclosed dark room has one window exposed to the
sun. This is shut by interior, opaque panels of oak, 15 mm
thick. Behind one of these panels, at any distance -- 1 meter,
for instance -- a thin glass tube is placed, containing a
phosphorescent substance, say calcium sulfide, which has been
previously exposed for a short time to solar rays. If, now, on
the path of the solar rays, which are supposed to reach the tube
through the wood, a sheet of lead, or the hand simply, is
interposed, even at a great distance from the tube, the
phosphorescent glow is seen to diminish; when the obstacle is
removed, the glow reappears. The extreme simplicity of this
experiment will incite many persons, I hope, to repeat it. The
only precaution one need take is to operate with a feeble
preliminary phosphorescence (note 9). It is advantageous to
arrange permanently a sheet of black paper, so that the
interposition of the screen does not change the background on
which the tube stands out. The variations in glow are especially
easy to catch near the contours of the luminous patch formed by
the phosphorescent body on the dark background; when the N rays
are intercepted, these contours lose their sharpness, regaining
the same when the screen is removed. However, these variations
in glow do not appear to be instantaneous. Interposing between
the shutter and the tube several sheets of aluminum, cardboard,
or an oak board 3 cm thick, does not hinder the phenomenon; any
possibility of an action of radiated heat, as such, is
consequently excluded. A thin film of water completely arrests
the rays; light clouds passing over the sun considerably
diminish their action.

The N rays emitted by the sun can be concentrated by a quartz
lens; by means of the phosphorescent substance, the existence of
several foci is ascertained. I have not yet determined their
positions with sufficient precision to speak of them here. The N
rays of sunlight undergo regular reflection by a polished plate
of glass, and are diffused by ground glass.

The N rays issuing from the sun increase the glow of a small
spark and a small flame in the same manner as those emitted by a
Crookes tube, by a flame, or by an incandescent body. These
phenomena are easy to observe, especially is use is made of an
interposed sheet of ground glass, as indicated by me in a
preceding communication. The use of a small flame is by far the
most convenient and precise of all processes for determining the
position of the foci. Operating with the small spark is much
harder, because the spark is rarely very regular.

I feel bound to reproduce, textually, here a passage in a
letter which M. Gustave le Bon had done me the honor of writing:

"M. Gustave le Bon had indicated, as far back as 7 years ago,
that flames emit, independently of the radioactive emanations
observed by him, radiations of large wavelength, capable of
traversing metals, and to which he had given the name of black
light; but while assigning these a place intermediate between
light and electricity, he had not exactly measured their
wavelength, and the method he had employed to reveal their
presence was very uncertain."

The method referred to was the photographic method. Personally,
I have not been able to obtain any photographic effect of the
rays I have studies.

**(6)  On a New Action Produced by N Rays, and on Several
Facts Connected with These Radiations (July 20,1903)**

The action of N rays on a small flame gave me the idea of
trying whether they did not exercise an analogous action on a
solid incandescent body. For this purpose a platinum wire, about
0.1 mm diameter and 15 mm long, was heated to dull redness by an
electric current. A pencil of N rays, emitted by an Auer burner,
was directed through wood and aluminum screens on this wire, and
was concentrated by a quartz lens.

The wire was observed through a plate of ground glass, fixed to
the same support as the wire itself, and about 3 cm in front of
it. On displacing the wire, several foci were found, just as
with other processes employed to detect N rays. The wire being
placed at one of these foci, the luminous patch on the ground
glass is seen to diminish in brightness when a lead screen, or
merely the hand, is interposed; when the obstacle is removed,
the light resumes its former brightness. These actions do not
appear instantaneous.

I have generalized the former experiments by employing, instead
of a wire heated by an electric current, a sheet of platinum 0.1
mm thick, inclined at 45 deg on the horizontal plane, partially
heated to a dark red by a small gas flame placed underneath. A
horizontal pencil of N rays, concentrated by a lens, was made to
impinge on the under face of the sheet, so as to produce a focus
at the heated spot; on the upper face the incandescent patch was
observed without interposing ground glass. The variations in
brightness are exactly analogous to those of the wire. When
observing, through ground glass, the intensity of illumination
of the bottom face of the sheet, due to the rays and the flame
together quite similar variations are found. Further, the same
results are obtained if, instead of making the rays fall on the
lower face, or the side on which the flame acts directly, they
are directed on the upper face.

The different effects produced by N rays, viz. their action on
a spark or flame, and on phosphorescent or incandescent bodies,
would lead to the supposition that they might also have a
heating effect on the bodies subjected to their action. To test
the matter experimentally, I installed a thermopile of Rubens
connected to an enclosed galvanometer. The action of N rays on
this apparatus was absolutely nil, even in the most favorable
conditions, though a candle placed 12 meters away gave a
deflection of about 0.5 mm on the scale. I conducted the
experiment not only with N rays proceeding from an Auer burner,
but also with those from the sun on July 3, 1904 [?], at midday.
The rays were very intense, for when I placed in front of the
thermopile a tube containing calcium sulfide, which had been
feebly excited by exposure to the sun, its glow was greatly
increased, but was diminished by the interposition of a lead
screen or the hand. M. H. Rubens made the same observation, as
he was kind enough to write me, his apparatus being much more
sensitive even than mine. I nevertheless thought it useful to
determine directly whether the incandescent platinum wire was
not heated by the action of N rays. To this end, I had recourse
to the study of its electric resistance. The current flowing
through the wire is produced by 5 accumulators; with the aid of
high-resistance rheostats, the intensity is adjusted to make the
platinum wire a dull red. The wire is stretched between two
massive brass pliers, A  and B, which are connected to the
terminals of a capillary electrometer; on one of the connecting
wires an adjustable electromotive force is inserted, obtained by
shunting a portion of the circuit of an auxiliary battery. This
electromotive force is regulated so that the electrometer is at
zero. Every variation in resistance of the platinum wire
produces a deviation of the electrometer. Now, with N rays
playing on the wire, no deviation of the meniscus was observed.
The interposition of a lead or wet-paper screen remained without
effect on the electrometer, though the wire underwent the usual
variations in brightness. This certainly proves that N rays do
not raise its temperature. I assured myself moreover that the
method was sufficiently sensitive by the following experiment;
by means of a wire rheostat, an assistant varied the resistance
of a circuit containing the platinum wire and the accumulators,
and consequently the strength of the current, but not
sufficiently for the observer to perceive a variation in the
glow of the wire. In spite of this, the electrometer was
deflected three divisions of the micrometer in the eye-piece.
The following is another verification: raising the temperature
of the wire one degree would alter its resistance in the ratio
of about 1.004 to one; the difference of potential between A and
B would alter in about the same ratio, since the resistance
external to the wire being very great, the current strength does
not change. In my experiments this variation would deflect the
electrometer by 15 divisions. As absolutely no deviation
occurred, and as, moreover, a quarter of a division could have
been easily observed, the rise in temperature is certainly very
inferior to 1/15 x 1/4 = 1/60 of a degree, and, consequently,
quite insufficient to produce the observed increase in glow. It
is thus superabundantly established that the increase in glow
produced by the rays is not due to a rise in temperature.

In the experiments with a plate of platinum, mentioned above,
the increase in glow was apparent on the two faces of the sheet,
Given that there is no rise in temperature, this seems
paradoxical; for since N rays do not go through platinum, it
seemed as if the action should only appear on the side exposed
to these rays. To reconcile these results, it was necessary to
suppose that N rays, which do not traverse cold platinum,
traverse it when incandescent. I then reverted to the apparatus
which was destined to show the action of N rays on a small
flame, and behind the quartz lens I arranged a platinum sheet
larger than the lens. The interposition of a lead screen between
the platinum and the source produced no effect on the small
flame, and the source produced no effect on the small flame,
which verifies the opacity of platinum. The plate being then
heated to redness, interposing the screen was seen to diminish
the glow of the small flame. N rays issuing from an Auer burner
traverse therefore incandescent platinum.

**(7)  On New Actions Produced by N Rays --
Generalization of the Phenomena Already Observed (November 2,
1903)**

When a pencil of N rays is directed either on a small spark,
flame, or a phosphorescent substance previously exposed to the
suns rays. Or, again, to a platinum plate heated to dull
redness, the light emitted by these various sources is seen to
increase in glow. In these experiments, one operates on sources
emitting light spontaneously. I asked myself whether one could
not generalize these experiments by using a body not emitting
light itself, but reflecting that which reaches it from an
external source. I consequently carried out the following
experiment: a slip of white paper, 15 mm long and 2 mm broad, is
fixed vertically to a wire holder; the room being made dark, the
slip is dimly lit b projecting laterally on it a pencil of
light, emitted by a small flame shut up in a box, in which a
vertical slit is pierced.

On the other hand, the rays are produced by the following
contrivance: an Auer burner, provided with a sheet-iron chimney,
in which a rectangular orifice, 60 mm high and 25 mm broad, has
been cut, is enclosed in an iron lantern pierced with an opening
placed in front of the chimney orifice, and stopped by a plate
of aluminum. In front of this window the small slip of paper is
placed, illuminated in the manner indicated above. If, now, the
rays are intercepted by interposing a sheet of lead or the hand,
the small paper rectangle is seen to darken, and its contours to
lose their sharpness; the light diffused by the slip of paper is
thus increased by the action of N rays.

The following idea then presented itself: the diffusion of
light is a complex phenomenon, in which the elementary fact is
regular reflection, and consequently there is reason for
ascertaining experimentally whether the reflection of light is,
or is not, modified by the action of N rays. For this purpose, a
polished steel knitting needle was fixed vertically in place of
the slip of paper of the former experiment; at the same time, in
a box completely closed, with the exception of a vertical slit
cut at the same height as the Auer burner, and stopped up by
transparent paper, a flame was disposed so as to light up the
slit.. By suitably placing the eye and the slit, the image of
this latter is seen formed by reflection on the steel cylinder,
and simultaneously the reflecting surface is receiving the N
rays. It is then easy to observe that the action of these rays
reinforces the image, for if they are intercepted, the image
darkens, and turns to a reddish hue. I repeated this experiment
with the same success by employing, instead of the knitting
needle, a plane mirror of bronze.

The same result is again obtained by reflecting the light on
the polished face of a block of quartz. However, when the N rays
fall normally on the refracting face, their action on the
reflected light disappears, whatever be the incidence of this
light, whether it be that their action becomes zero, or simply
inappreciable. In order that the light reflected by the quartz
may be reinforced by the N rays, it is not necessary that the
rays should be directed towards the interior of the quartz; the
action still occurs when the N rays traverse the reflecting
surface from the inside towards the outside.

All these actions of N rays on light require an appreciable
time-interval for appearing and disappearing. I was unable,
although I varied the experiment in a great many ways, to
observe any action of N rays on the refracted light.

I will here make the following general remark concerning the
observation of N rays. The aptitude for catching small
variations in luminous intensity is very different in different
persons; some see from the outset, and without any difficulty,
the reinforcing action produced by N rays on the brightness of a
small luminous source; for others, these phenomena lie almost at
the limit of what they are able to discern, and it is only after
a certain amount of practice that they succeed in catching them
easily, and in observing then with complete certainty. The
smallness of the effects and the delicacy of their observation
must not deter us from a study which puts us in possession of
radiations hitherto unknown. I have recently observed that the
Auer burner can be advantageously replaced by the Nernst lamp,
without a glass, this lamp giving more intense N rays. With a
200-watt lamp, the phenomena are marked enough to be, in my
belief, easily visible to any one at the first trial.

**(8)  On the Storing-up of N Rays by Certain Bodies
(November 9, 1903)**

In the course of my researches on N rays, I had occasion to
note a very remarkable fact. The N rays were produced by an Auer
burner enclosed in a lantern, and after passing through one of
the sides of the lantern, formed by a sheet of aluminum, were
concentrated by a quartz lens upon phosphorescent calcium
sulfide.

This sulfide was tightly packed into a slit cut into a sheet of
cardboard 0.8 mm thick; the width of the slit was 0.5 mm and its
length was 15 mm. After exposure to sunlight, a small luminous
source is thus obtained, which is very sensitive to N rays.

An Auer burner having been extinguished and removed the
phosphorescent glow, to my great surprise, remained almost as
strong as ever, but was darkened by the interposition of lead,
or wet paper, or the hand, between the lantern and the sulfide.
Nothing was altered by the suppression of the Auer burner,
except that the observed actions grew progressively weaker. At
the end of 20 minutes they still existed, but were scarcely
noticeable.

Studying closely the circumstances of the phenomenon, I was not
long in recognizing that the quartz lens had itself become a
source of N rays; for when this was removed, all action on the
sulfide ceased, whereas if it was brought nearer the sulfide,
even laterally, the latter would become more luminous. I then
took a quartz plate 15 mm thick, whose surface formed a square
of 5 cm sides, and exposed this to the N rays emitted by an Auer
burner through two sheets of aluminum and some black paper. It
became as active as the lens; when brought nearer the sulfide,
it seemed, according to Bichats expression, as if a veil
darkening was being removed. A still more marked effect was
obtained by interposing the quartz plate between the source and
the sulfide, quite close to the latter.

In these experiments, the secondary emission by the quartz is
added to the N rays directly emanating from the source. This
secondary emission has, indeed, its origin in the whole mass of
the quartz, and not at the surface only, for if several plates
of quartz be successively placed on top of each other, the
effect is seen to increase with each added plate. Iceland spar,
fluorspar, barite, glass, etc, behave like quartz. The filament
of a Nernst lamp remains active for several hours after the lamp
is extinguished.

A piece of gold, laterally brought near to the sulfide while it
is being subjected to N rays, increases its glow (note 10).
Lead, platinum, silver, zinc, etc. produce the same effects.
These actions persist after the extinction of the N rays, as in
the case of quartz.

Nevertheless, the property of secondary ray emission only
permeates slowly through a metallic mass. Thus, if one of the
faces of a sheet of lead 2 mm thick has been exposed to N rays
for several minutes, this face alone shows activity; an exposure
of several hours is necessary for the activity to reach the
opposite face.

Aluminum, wood, dry or wet paper, and paraffin do not enjoy the
property of storing N rays. Calcium sulfide, on the other hand,
does possess this property. When I put a few grams of sulfide in
an envelope, and then exposed the envelope to N rays, I found
that its proximity was sufficient to reinforce the
phosphorescence of a small mass of previously excited sulfide.
This property explains a constant peculiarity that I have
previously set forth, viz., that the increase of phosphorescence
under the action of N rays takes an appreciable time to appear
or to disappear. For, thanks to the storing-up of the N rays,
the different parts of a mass of sulfide mutually reinforce
their phosphorescence; but since, on the one hand, this
reinforcing is progressive, as I have proved, and since, on the
other hand, the stored-up provision is not immediately
exhausted, the result is that when N rays are made to fall on
phosphorescent calcium sulfide, their effect must increase
slowly, and that when they are suppressed, their effect can only
disappear slowly.

I repeat here that, as a rule, when experimenting with N rays,
it is advantageous to replace the Auer burner by a Nernst lamp
absorbing about 200 watts.

Pebbles picked up at about 4 p.m. in a yard where they had been
exposed to the sun, spontaneously emitted N rays; bringing them
near a small mass of phosphorescent sulfide was sufficient to
increase its luminosity. Fragments of calcareous stone, brick,
etc., picked up in the same yard, produced analogous actions.

The activity of all these bodies still persisted after 4 days,
without any sensible diminution. It is, however, necessary for
the manifestation of such actions that the surface of these
bodies be quite dry; for we know that the thinnest layer of
moisture is sufficient to arrest N rays. Vegetable earth was
found to be inactive, doubtless on account of its moisture;
pebbles taken from several centimeters underneath the surface of
the soil were inactive, even after being dried.

The phenomena of the storing-up of N rays, which are the object
of the present note, ought naturally to be compared with those
of phosphorescence; yet they present a quite distinct feature,
as I intend to show shortly.

**(9)  On the Strengthening Action of a Beam of Light on
the Eyes, When the Beam is Accompanied by N Rays (November 23,
1903)**

While studying the storing-up of N rays by different bodies, I
had occasion to observe an unexpected phenomenon. My eyes were
fixed on a small slip of paper, dimly lit, about 1 meter distant
from me; a brick, one of whose faces had been sun-exposed,
having been brought nearly laterally to the luminous pencil,
with its sun-exposed face turned towards me, and a few
decimeters distant form my eyes, I saw the slip assume a
heightened glow; when the brick was removed, or when its
non-exposed face was turned towards me, the paper grew darker.
To remove all possibility of illusion, I arranged permanently a
box closed by a cover and wrapped in black paper; in this
completely enclosed box the brick was placed, the dark
background on which the slip stood out remained rigorously
invariable, but the observed effect remained the same. The
experiment can be varied in different ways. For instance, the
laboratory shutters being almost closed, and the dial of the
clock fixed to a wall which was just sufficiently lighted for
the dial, at a distance of 4 meters, to be just perceived as a
grey patch with no defined contour, if the observer, without
changing his place, directs towards his eyes the N rays emitted
by a previopusly exposed brick or pebble, he sees the dial
whiten; he can trace distinctly its circular contour, and even
succeed in seeingthe hands. When the N rays are suppressed, the
dial again grows dark. Neither the production nor the cessation
of the phenomenon are instantaneous.

As in these experiments the luminous object is placed very far
away from the source of N rays, and as, on the other hand, in
order that the experiment may succeed, the rays must be
directed, not towards the object, but towards the eye, there can
be no question here of an increase in emission of a luminous
body influenced by N rays, but indeed of a strengthening of the
effect upon the eye, due to the N rays which are superposed on
the luminous rays.

This fact astonished me all the more because, since the
slightest film of water arrests N rays, it seemed unlikely that
they could penetrate into the eye, whose humours contain more
than 98.6% of water (Lohmeyer). The small quantity of slat
contained in these humours must have rendered them transparent
to N rays. But then, in all probability, salt water must itself
be transparent. Experiment shows that this is the case, for
while a sheet of wet paper completely arrests the N rays, a vase
of Bohemian glass, 4 cm thick, filled with salt water and placed
in their path, lets them pass without sensible weakening. A very
small quantity of sodium chloride is sufficient to render water
transparent. What is more, salt water is capable of storing-up N
rays, and in the above-described experiments the brick can be
replaced by a vase of thin glass, filled with salt water, and
previously exposed to the suns rays; the effect is very marked.
It is certainly due to the salt water, for the empty vase is
without effect. This is a unique example of a phosphorescence
phenomenon in a liquid body. It is true that the wavelengths of
N rays are very different from those of luminous rays, as
results from measurements which it is my intention to describe
very soon.

The eye of an ox, killed the day before, rid of its muscles and
the tissues adhering to the sclerotic, proved to be transparent
to N rays in all directions, and became itself active by
sun-exposure; it is the storing-up of the N rays by the media of
the eye which causes the retardation observed in the appearance
and cessation of the phenomena which are the subject to the
present note.

Sea water and the stones exposed to solar radiation store up N
rays which they afterwards restore. Possibly these phenomena
play some hitherto unperceived part in certain terrestrial
phenomena. Perhaps, also, N rays are not without influence on
certain phenomena of animal and vegetable life.

The following are further observations concerning the
strengthening action of N rays on luminous rays.

It is sufficient for the production of the phenomenon that the
N rays reach the eye, no matter how, even laterally. This seems
to indicate that the observers eye behaves like an accumulator
of N rays, and that it is these rays accumulated in the eye
which act on the retina, jointly with luminous rays.

It matters little whether in these experiments the rays are
emitted by a body previously exposed to the sun, or are primary
rays, produced for instance by a Nernst lamp.

Sodium hyposulfite, whether solid or dissolved in water,
constitutes a powerful accumulator of N rays.

**(10)  On the Property of Emitting N Rays, Which is
Conferred on Certain Bodies by Compression, and on the
Spontaneous and Indefinite Emission of N Rays by Hardened
Steel, Unannealed Glass, and Other Bodies in a State of
Strained Molecular Equilibrium (December 7, 1903)**

Prof. A. Charpentier kindly undertook to keep me informed with
regard to the progress of certain researches of a physiological
nature which he is conducting in connection with N rays,
unpublished researches which (note 11) promise highly
interesting results. These experiments led me to the idea of
examining whether certain bodies did not acquire, by
compression, the property of emitting N rays. For this purpose I
compressed, by means of a carpenters press, bits of wood,
glass, rubber, etc., and I immediately observed that these
bodies had in fact become, during the compression, sources of N
rays; brought neat a mass of phosphorescent calcium sulfide,
they increased its luminosity; and they can also be used for
repeating the experiments which show the strengthening of the
action on the retina by light when N rays are acting
simultaneously on the eye.

These last experiments may be made in a very simple manner. The
shutters of a room should be closed so as to leave just enough
light for a white surface standing on a dark background -- for
instance, the dial of a clock -- to appear, before an observer 4
or 5 meters distant, like a grey patch with ill-defined
contours. If a can stick placed before the eyes is bent, the
grey surface is seen to whiten; if the cane is allowed to
straighten, the surface grows dark again. Instead of the cane, a
slip of plate-glass can be used. If this is bent wither with the
press employed in lectures for showing the doubly refractive
property of glass acquired by flexure, or simply with the hands.
With a suitable amount of light, which may be obtained after a
few trials, these phenomena are easily visible. They are not
instantaneous, as I have already explained. It is of the utmost
importance that this retardation be taken into account when one
wishes to study these phenomena; to this may doubtless be
ascribed the fact that they have remained so long undetected.

I was then led to ask myself whether bodies which are
themselves in a state of strained internal equilibrium would not
emit N rays. That they do so in indeed confirmed by experiment.
Ruperts drops, hardened steel, hammer-hardened brass, melted
sulfur of crystalline structure, etc., are spontaneous and
permanent sources of N rays. One can, for instance, repeat the
experiments with the clock dial, employing, instead of a
compressed body, a hardened steel tool, such as a chisel or
file, or even a pocket-knife, without in any way bending or
compressing them; similarly, bringing near to a small mass of
phosphorescent calcium sulfide a knife-blade or a bit of
unannealed glass is sufficient to increase the phosphorescence
Non-hardened steel is without action; a chisel which is
successively hardened and softened in turn is active when hard
and inactive when the temper is taken out of it. These actions
traverse, without any notable weakening, a plate of aluminum 1.5
cm thick, an oak board 3 cm thick, black paper, etc.

The emission of N rays by tempered steel seems to last
indefinitely. Some lathe tools and a stamp for leather of the
18th century, which have been preserved in my family, and have
certainly not been rehardened since the date of their
manufacture, emit N rays like freshly tempered steel. A knife,
found in a Gallo-Roman tomb, situated in the district of
Craincourt (Lorraine), and dating from the Merovingian epoch, as
is attested by the objects found there (glass and earthenware
jars, fibulae, belt buckles, etc.), emits N rays just kike a
modern knife. These rays originate exclusively from the blade; a
test with a file showed that the blade alone is tempered, and
that the tailpiece intended to be fixed in a handle is not
tempered.

The emission of N rays by this steel blade has thus persisted
for more than 12 centuries, and does not appear to have abated.

The spontaneity and the indefinite duration of the emission by
steel suggests the idea of assimilating it to the radiant
properties of uranium, discovered by M. H. Becquerel, properties
which the bodies since discovered by M. and Mme. Curie, viz.
radium, polonium, etc., exhibit with so much intensity.
Nevertheless, N rays are certainly spectrum radiation; they are
emitted by the same sources as spectrum radiation; they are
reflected and polarized, and possess well-defined wavelengths,
which I have measured. The energy which their emission
represents is most likely borrowed from the potential energy
corresponding to the strained state of tempered steel; this
expenditure is doubtless very slight, since the effects of the N
rays are likewise slight, which explains the apparently
unlimited duration of the emissions.

An iron plate, bent so as to impress on it a permanent
deformation, emits N rays; but the emission ceases after a few
minutes. A block of aluminum, fresh-hammered, behaves in an
analogous manner; but the time of emission is even shorter. In
these two cases the state of molecular strain is transitory, as
is also the emission of N rays.

Torsion produces effects analogous to compression.

**(11) On the Dispersion of N Rays and on their Wavelength
(January 18, 1904)**

To study the dispersion and the wavelengths of N rays, I used
methods quite similar to those employed for light. In order to
avoid complications which might have resulted from the
storing-up of N rays, I used exclusively prisms and lenses of
aluminum, a substance which does not absorb their rays.

The following is the method employed to study dispersion. The
rays are produced by a Nernst lamp, enclosed in a lantern of
sheet-iron, pierced with an opening, which is shut by aluminum
foil; the rays from the lamp which pass through this opening are
sifted by a deal board 2 cm thick, a second sheet of aluminum,
and two leaves of black paper, so as to eliminate radiations
foreign to N rays. In front of those screens, and at a distance
of 14 cm from the lamp filament, a large screen of wet cardboard
is arranged, in which a slit has been cut 5 mm wide and 3.5 cm
high, exactly opposite the lamp filament. In this way I obtain a
well-defined pencil of N rays; this pencil is received on an
aluminum foil prism whose refractive angle is 27 deg 15, placed so
that one of its faces is normal to the incident pencil.

It is, then, possible to prove that from the other refractive
face of the prism several pencils of N rays, horizontally
dispersed, emerge. For this purpose a slit 1 mm broad and 1 cm
high, cut in a sheet of cardboard, is filled with calcium
sulfide rendered phosphorescent; by displacing this slit, the
position of the dispersed pencils is determined without
difficulty, and the deviations being known, their refractive
indices are deduced. This is the method of Descartes. I thus
established the existence of N radiations, whose indices are
respectively 1.04, 1.19, 1.29, 1.36, 1.40, 1.48, 1.68, and 1.85.
In order to measure with more exactness the first two indices I
made use of another aluminum prism having an angle of 60 deg, I
again found for one of the indices the same value, 1.04; and for
the other, 1.15 instead of 1.19.

In order to control the results obtained by the prisms, I
determined the indices by producing, by means of an aluminum
lens, images of the lamp filament, and measuring their distances
from the lens. The lens, which is plano-convex, has a radius of
curvature of 6.63 cm, and an aperture of 6.89 cm. The slit of
the wet screen is widened so as to form a circular opening 6 cm
in diameter; the lens is placed at a known distance ( *p*
cm) from the incandescent filament, and by means of the
phosphorescent sulfide, the position of the conjugate images of
the filament is determined. The following table gives the values
of the indices found, both with the prism and the lens: ---

Prisms:   
27 deg 15 ~ 60 deg   
1.85 ~ "   
1.68 ~ "   
1.48 ~ "   
1.40 ~ "   
1.36 ~ "   
1.29 ~ "   
1.19 ~ 1.15   
1.04 ~ 1.04

Lens:   
*P* = 40 ~ *p* = 30  ~ *p* = 22 cm   
1.86 ~ 1.91 ~ 1.91   
1.67 ~ 1.66 ~ 1.67   
1.50 ~ 1.44 ~ 1.48   
1.42 ~ 1.42 ~ 1.43   
1.36 ~ 1.36 ~ 1.37   
1.36 ~ 1.31 ~ "   
1.20 ~ " ~ "

Here is another verification of these results: if for the
fourth index the mean value 1.42 is adopted, one works out that
for an aluminum prism of 60 deg, the incidence giving the minimum
deviation is 45 deg 19, and that this deviation is 30 deg 38; the
observed deviation was 31 deg 10. With the same incidence, the
calculated deviation of the radiation, whose index is 1.67, is
57 deg 42; the observed deviation was 56 deg 30.

I now pass on to the determination of wavelengths.

By means of the above-described arrangement for studying
dispersion by the prism of 27 deg 14, refracted pencils are
obtained, each of which is sensibly homogeneous. If we make the
pencil we wish to study impinge on a second screen of wet
cardboard, pierced with a slit 1.5 mm wide, we can isolate a
narrow portion of this pencil.

On the other hand, a piece of aluminum foil is fixed to the
moving radial arm of a goniometer, so that its plane is normal
to the arm; in this foil a slit is cut only 0.07 mm wide, and
filled with phosphorescent calcium sulfide; the goniometer is
arranged so that its axis is exactly underneath the slit of the
second wet cardboard. By turning the arm, the path of the pencil
is exactly marked out, and one can verify that it is quite
unique, and is accompanied by no lateral pencil, such as
diffraction could eventually produce in the case of large
wavelengths.

A grating is then placed in front of the slit of the second wet
cardboard (for instance, a Brunner grating of 200 lines per mm).
If, now, the emerging pencil is explored by turning the arm
which bears the phosphorescent sulfide, the existence of a
system of diffraction fringes is confirmed, just as with light,
only these fringes are much closer together, and are sensibly
equidistant. This already indicates that N rays have much
shorter wavelengths than luminous radiations.

The angular distance of the fringes, or what amounts to the
same thing, the rotation of the arm corresponding to the passage
of the phosphorescent slit from one luminous fringe to the next,
is very small. It is therefore determined by the method of
reflection, with the aid of a divided scale and telescope, a
plane-mirror being fixed to the arm. Moreover, one measures, not
the distance between tow consecutive fringes, but that between
two symmetrical fringes of a high order -- for example, that
between the tenth fringe on the right, and the tenth fringe on
the left. From these measures of angle, and from the number of
lines per millimeter of the grating, the wavelength can be
deduced by the known formula.

Each wavelength has been determined by three series of
measurements, effected with three gratings, having respectively
200, 100, and 50 lines per millimeter.

The following table exhibits the results of these measures:

*Wavelengths:*   
Indices ~ 200 lines/mm ~ 100/mm ~ 50/mm ~ Probable Values

1.04 ~ 0.00813 ~ 0.00795 ~ 0.00839 ~ 0.00815   
1.19 ~ 0.0093 ~ 0.0102 ~ 0.0106 ~ 0.0099   
1.4 ~ 0.0117 ~ " ~ " ~ 0.0117   
1.68 ~ 0.0146 ~ " ~ " ~ 0.0146   
1.85~ 0.0176 ~ 0.0171 ~ 0.0184 ~ 0.0176

Being desirous of controlling these determinations by the use
of a quite different method, I had recourse to Newtons rings.
These being produced, in yellow light, for instance, of one
passes from one dark ring to the following, the variation of
optical retardation in air is one wavelength of yellow light.
If, now, with the same apparatus and the same incidence, rings
are produced by means of N rays, and the number of these rings
comprised between two dark rings in yellow light is counted, we
shall obtain the number of times which the wavelength of N rays
is contained in the wavelength of yellow light. This methods,
applied to rays of index 1.04, gave the values of 0.0085 instead
of 0.0081 found by the gratings; and for the index 1.85, the
value 0.017 instead of 0.0176. Though the ting method is
inferior to the grating method, on account of the uncertainty
attending the exact position of the dark rings in the
experiment, an uncertainty which is due to the necessity of
rendering these rings very wide, the concordance of the numbers
obtained by the two methods constitutes a valuable control.

In the tables given above I have retained all the decimals
occurring in the calculation of the numbers deduced from
observation. Although I cannot with certainty indicate the
degree of approximation of the results, I believe, nevertheless,
that the relative errors do not exceed 4 percent.

The wavelength of N rays are much smaller than those of light.
This is contrary to what I had imagined for a moment, and
contrary to the determinations which M. Sagnac thought he had
deduced from the position of the multiple images of a source,
obtained with a quartz lens, images attributed by him to
diffraction. I had previously observed that while polished mica
lets N rays pass, roughened mica stops them, and also that
whereas polished glass reflects them regularly, ground glass
diffuses them. These facts were already an explanation that N
rays could not have large wavelengths. If we desire to study the
transparency of a body, we must take care that the surface is
well polished. Thus I had at first classed rock salt amongst
opaque substances, because the specimen I used, having been sawn
from a large block, had remained unpolished; in reality, rock
salt is transparent.

The radiations of very small wavelength, discovered y M.
Schumann, are to a very great extent absorbed by air; N rays are
not. This implies the existence of absorption bands between the
ultraviolet spectrum and N rays. The wavelength of N rays
increases with their refractive index, contrary to what occurs
with luminous radiations.

If the increase in brilliancy of a small luminous source by the
action of N rays is to be attributed to a transformation of
these radiations into luminous radiations, this transformation
is in conformity with Stokeslaw.

**(12) Registration by Photography of the Action
Produced by N Rays on a Small Electric Spark (February 22,
1904)**

Though N rays have no intrinsic action on the photographic
plate, it is nevertheless possible to utilize photography to
reveal their presence and study their action. This object is
attained, as I showed as long ago as May 11, 1903, by making a
small, luminous source act for a determined period on a
sensitive plate, whilst this source is subjected to the action
of N rays, and then repeating the experiment for the same
interval of time and under the same conditions, save that the N
rays are suppressed. The impression produced is notably more
intense in the first case than in the second. As an example of
the application of this method, I gave at the time two
photoengravings, whose comparison shows that water, even when
used in very thin films, arrests N rays issuing from an Auer
burner. Since then I have extended the experiments to the
registration of actions produced by N rays from various sources,
and I have perfected the process, as will be shown.

A small, luminous spark is the most appropriate luminous source
for this kind of investigation: for, on the one hand, it is very
actinic, and, on the other, it can be maintained as long as
necessary at the same intensity. Although it is impossible to
obtain absolute steadiness of glow in the spark, since these
variations are not produced symmetrically, their influence
should disappear in the total impression received by the plate,
even after a very short exposure. I contrived, besides, to
eliminate even still more completely this cause of perturbation,
by repeatedly alternating the experiments, as I will proceed to
show.

Figure 4 represents a horizontal section of the apparatus
employed. AB is the photographic plate, 13 cm wide; E is the
spark enclosed in a cardboard box, FGHI, open only on one side
facing the plate, and allowing the spark to act on one half, OB,
of the plate only; CD is a lead screen wrapped in wet paper,
rigidly connected with the frame which holds the plate. The N
rays, proceeding from any source, form a pencil, having the
direction NN. With this arrangement the N rays are arrested by
the screen CD; the spark, while it acts on half-plate OB, is
sheltered from the rays.

***Figures 4, 5 ~***

![](0blo3.gif)

Now impart to the frame containing the plate a translation to
the right equal to half its length (Figure 5); the other half,
AO, of the plate takes the place formerly occupied by OB; and
this time the screen CD, carried along with the frame in this
movement, is no longer interposed in the path of the rays. The
half-plate AO therefore receives the action of the spark while
subjected to the rays.

This being understood, the experiment is as follows: first the
plate is kept in the first of the above-indicated positions
during 5 seconds, then in the second position also for 5
seconds; it is then brought back to the first position, and the
double operation just described is repeated several times.

After an interval of time equal to an even multiple of 5
seconds -- for instance, 100 seconds -- each of the half-plates
has been exposed to the spark for an equal period, only, while
AO was exposed, N rays were in action, and while OB was exposed
there were none.

Thanks to an arrangement of guides and buffer-stops, the
to-and-fro motion of the frame can be executed with perfect
certainty and regularity, in spite of the darkness. A metronome
is used to regulate the action.

The spark is produced by a small induction-coil, known as du
Bois-Reymonds chariot apparatus; it strikes between two blunt
points of platinum-iridium, carefully machined and polished.
These are fixed to the two jaws of a pair of wooden pliers which
tend to close by elasticity, and are kept apart by a micrometer
screw. At a distance of about 2 cm from the spark, and facing
the plate, a plate of ground glass is fixed. As I have
previously mentioned, the light of the spark produces on this
plate an extensive luminous patch, much easier to observe than
the naked spark, and giving on the photographic plate
impressions of much more regular form. The regulating of the
spark is the delicate part of the experiment. The induced
current must first be adjusted, by modifying the primary current
on the one hand, and the position of the secondary coil on the
other, till the spark becomes very small. The points are washed
in alcohol, then a slip of dry paper is drawn between them, for
the purpose of drying and repolishing their surface; then the
micrometer screw s turned so as to make the spark as short as
possible, yet without incurring any risk of the points touching
by any chance vibration, which would make it disappear
intermittently. By a methodical process of trial and error,
which sometimes demands much time and patience, one succeeds in
getting a spark both regular and very feeble; it is then
sensitive to the action of N rays. If one directs on it a pencil
of these radiations, proceeding from any source, one sees the
patch on the ground glass increase in size and glow; at the same
time its central part becomes more luminous, appearing wrapped
in a kind of nimbus. One can then proceed with the photographic
experiment. I made about 40 such experiments, employing in turn,
as sources of N rays, a Nernst lamp, compressed wood, hardened
steel, Ruperts drops, etc. I have varied the experiments in
different ways -- for example, by changing the side of the
screen CD, by using a zinc screen transparent to N rays, etc.
Several eminent physicists, who have been good enough to visit
my laboratory, have witnessed them. Of these 40 experiments, one
was unsuccessful: the rays were produced by a Nernst lamp, and
instead of the expected unequal impressions, two sensibly
identical images were obtained. I believe this failure, unique,
be it remarked, to be due to an insufficient regulation of the
spark, which, doubtless, was not sensitive. Figure 6 is a
photo-engraved reproduction of the prints obtained with and
without N rays issuing from a Nernst lamp.

***Figures 6, 7***

![](0blo4.gif)

Figure 7, similarly, shows the result of an experiment with N
rays, produced by two large files.

Though the photogravures are far from rendering in a
satisfactory manner the aspect of the originals, they
nevertheless show the influence of N rays on a photographic
impression.

I give further (Figures 8 and 9) the reproduction of
photographs, showing that N rays, issuing from a Crookes tube,
are polarized.

These photographs date from the month of April 1903. They were
not obtained by the method of reiterated alternation of
exposure, as this method is difficult to apply to this case; but
the experiments have been repeated a great number of times with
the most minute precautions, and the constancy of the results is
an absolute guarantee of their worth.

From my communication of May 11, 1903, and from what precedes,
it is clear that from the beginning of my researches on N rays,
I had succeeded in recording their action on the spark by an
objective method.

***Figures 8, 9***

![](0blo5.gif)  
**~**

**(13)  On a New Species of N Rays (February 29,
1904)**

Observations made during a very complex experiment, which I owe
to Dr. Th. Guidloz, led me to suspect the existence of a variety
of N rays, which, instead of increasing, on the contrary,
diminished the glow of a feeble luminous source. I undertook to
search for rays of this type amongst those emitted by a Nernst
lamp. While previously studying the spectrum of this emission,
produced by an aluminum prism, I had not met with such
radiations. I consequently thought that there were reasons for
studying anew, and still more minutely, the feebly deviated part
of the spectrum. On exploring this region, by means of a narrow
slit filled with phosphorescent calcium sulfide, I ascertained,
without any difficulty, that, in certain azimuths, the glow of
the spark diminished under the action of the rays, and
increased, on the contrary, when they were intercepted by a wet
screen. These were, in fact, the looked-for radiations; I will
call them N1 rays.

Although the aluminum prism of 27 deg 15 I used previously is
suitable for these experiments, nevertheless, in order to
increase the dispersion, I used an aluminum prism of 60 deg, and
afterwards another of 90 deg. With the help of the latter, I very
carefully studied the feebly deviated part of the spectrum. The
prism was arranged so that the angle of incidence was 20 deg; for
each radiation, the deviation was measured and the refractive
index deduced; then the wavelength was determined by means of a
Brunner grating of 200 lines per millimeter, by the process
already described. The following table gives the numbers which
result from this study, and were used for constructing the
diagram (Figure 10), in which the abscissae stand for the
wavelengths and the ordinates for the indices diminished by
unity.

*Nature of Rays ~ Indices ~ Wavelengths*

N1 ~ 1.004 ~ 0.003   
N ~ 1.0064 ~ 0.0048   
N1 ~ 1.0096 ~ 0.0056   
N ~ 1.011 ~ 0.0067   
N1 ~ 1.0125 ~ 0.0074   
N ~ 1.029 ~ 0.0083   
N ~ 1.041 ~ 0.0081

Each of the divisions marked on the axis of abscissae
corresponds to 0.001, and each of the divisions marked on the
ordinate axis corresponds to an excess over unity equal to 0.01.

In spite of all the care with which the experiments were
executed, the deviations are so small, and, consequently, the
indices so near to unity, that the table and diagram can only be
regarded as a preliminary indication of the behavior of the
dispersion in the very slightly deviated part of the spectrum.
An important consequence arises from these measures, viz. points
corresponding to N rays, and those corresponding to N1
rays, are all situated on the same curve, within the limits of
experimental error. The study of radiations still less
refrangible than those I have dwelt on appeared to me
impracticable. To avoid confusion, I was obliged to adopt a very
large scale for the ordinates; this is why I could not plot on
the diagram the results of my former measurements of the more
refrangible N rays. These results give points situated on a
branch of the curve, starting from the topmost point on the
right, and rising almost vertically, with a feeble inclination
from bottom to top, and from right to left, and a slight
convexity turned upwards.

Certain sources seem to emit N1 rays exclusively,
or, at least, these rays predominate in the emission. This is
the case with copper and silver wire, and with hard-drawn
platinum wire. M. Bichat has observed that ethylic ether, when
brought to the state of forced extension, by the process
discovered by M. Berthelot, emits N1 rays. When this
state of strain ceases, whether spontaneously or under the
action of a slight blow, the emission of N1 rays immediately
disappears.

N1 rays can be stored up like N rays. For instance,
one need only bring a bit of stretched copper wire in proximity
to a lump of quartz to make the quartz emit N1 rays
for some time after.

***Figure 10***

![](0blo6.gif)

**(14)  On Peculiarities Presented by the Action
Exercised by N Rays on a  Dimly Lighted Surface (February
2, 1904)**

Consider a phosphorescent screen, or, more generally, a dimly
lighted surface. If this surface is viewed normally, one notices
that the action of N rays is to render it more luminous; if, on
the contrary, the surface is viewed very obliquely, nearly
tangentially, the action of N rays is to render it less
luminous. In other words, the action of N rays increases the
quantity of light normally emitted, while it diminishes the
light emitted in a very oblique direction. If one looks at it in
an intermediate position, no appreciable effect is observed.
This explains the fact, observed in all N ray experiments, that
only the observer placed exactly in front of the sensitive
screen perceives the effect of these rays. It also shows how
illusory it would be to try to make an audience witness these
experiments; the effects perceived by different persons,
depending as they do on their positions with regard to the
screen, would certainly be contradictory or imperceptible. The
rays I have called N1 rays have an inverse action on
all cases to that of N rays; they diminish the light emitted
normally, and increase the light emitted tangentially. M. Mace
de Lepinay (see C.R. cxxxvii, p. 77, January 11, 1902) has found
that sound vibrations increase the glow of a phosphorescent
screen as seen by an observer viewing it normally. I have
noticed that if the screen is viewed tangentially, the
phosphorescence is seen to decrease under the action of the
sound waves. The action of a magnetic field or of an
electromotive force on a feebly luminous surface, discovered by
M. C. Gutton (see C.R., cxxxviii, p. 268, February 1, 1904),
presents the same particularities.

To sum up, in all the above-mentioned  actions, the
modification undergone by the luminous emission consists in a
change in its distribution along the different directions
comprised between the normal and the tangent plane to the
luminous surface.

**(15)  On the Comparative Action of Heat and N Rays on
Phosphorescence (March 14, 1904)**

I have recently indicated that, whilst the action of N rays
increases the quantity of light emitted by a phosphorescent
screen in a normal direction, it diminishes the quantity of
light emitted very obliquely. As is well known, heat also acts
on phosphorescence, whose brilliance it temporarily increases.
When investigating whether this action of heat offered the same
peculiarities as that on N rays, with regard to the direction of
the emitted light, I found that, on the contrary, heat produces
an increase in brilliancy in all directions comprised between
the normal and the tangent plane. Hence we are in a position to
distinguish between the effects produced on phosphorescence by
heat on the one hand, and by N rays, sound waves, magnetic and
electric fields on the other.

The following is another case in which the effects are
different. Take a rectangular cardboard screen, 5 cm high and 12
cm long, for instance, coated very uniformly with calcium
sulfide, and rendered very feebly phosphorescent. If the
temperature of a portion of the screen is raised, this part
becomes more luminescent than the rest. If, instead of this, we
let fall on one half of the screen a pencil of N rays,
proceeding, for example, from a Nernst lamp, we find no sensible
increase in its glow; but if in front of this half-screen a
small opaque object is placed, for instance, a small key or a
bit of metal foil, cut off by daylight, this is seen to come out
very strongly on the luminous background, while if it is placed
on the half not receiving the N rays, its outline is vague and
indeterminate, and seems even to disappear at times. By shifting
slowly the object on the screen, its passage from one
half-screen to the other is rendered visible by changes in the
boldness of its outline. If instead of viewing the object
normally, we observed it very obliquely, the phenomena are
reversed.

**(16)  Complementary Notes**

(1) As mentioned in the Preliminary Notice, and as will be seen
in the later communication, the properties attributed in the
present paper to X rays, belong not to these rays, but to a new
kind of rays, to which I have given the name of N rays. The
experiments are correct, and the rectification only applies to
the nature of the rays which have been studied.

(2)  What I attributed then to S rays is, in reality, die
to diffused N rays. The rotation of the plane of polarization of
N rays by active substances is perhaps very great, since their
wavelengths are very small. It may be, then, that the angles I
have observed are merely the remainders obtained by subtracting
360 deg once or several times from the real rotations. For the same
reason, the rotations in a contrary direction could be apparent
only. Investigation on this point remains still to be carried
out; the operations should be conducted successively on each of
the homogeneous pencils resulting from the dispersion of a
pencil of N rays by an aluminum prism. The existence of magnetic
rotary polarization has recently been shown by M. H. Bagard,
whose investigations are still in progress (C.R., cxxxviii).

(3) Unpolished mica arrests a pencil of N rays; these are not,
however, absorbed, but only diffused, as in the case of light.

(4) Rock salt is in reality transparent. What has at first
misled me was that the plate of salt I used, having been sawn
out of a large block, had remained unpolished. In this state it
was only translucent, whether for N rays or for light. When
polished with wet paper, it becomes transparent both for N rays
and light; when the polish disappears, it becomes translucent
again.

(5)  As I state in the text, these rough data on the
transparency of different substances will have to be completed
by new experiments methodically conducted. I have since found
that copper continues to transmit N rays emitted by a Nernst
lamp, even when used in thickness of 65 cm; that, similarly,
glass is very transparent, etc. M. Bichat has studied the
transparency of various bodies; in particular, he has
ascertained that the opacity of a sheet of lead is due to the
fact that it is superficially covered with oxide and carbonate.
Metallic lead lets pass certain of the N radiations (see C.R.
cxxxviii, p. 548, February 29, 1904).

(6)  See the communication of May 25 and June 15, 1903.

(7)  I have since found that, on the contrary, N rays have
much shorter wavelengths than those of light (See my
communication of January 18, 1904).

(8)  See note (7) above.

(9)  The phosphorescence may be intense, provided it be
not at its maximum.

(10) The piece of gold must of course be also receiving the N
rays.

(11)  These researches have since been communicated to the
Academy of Sciences (See C.R. cxxxvii, p. 1049, December 24,
1903).

(12)  According to some experiments which I have made with
an aluminum lens on rays issuing from a knife-blade, these
should have very large indices. M. Charpentier has found that
wet cardboard transmits these rays. These questions remain to be
studied.

**(17)  Instructions for Making Phosphorescent Screens
Adapted for the Observation of N Rays**

(1) If one proposes only to ascertain the production of N rays
in given circumstances, a phosphorescent screen, made as
follows, may be used with advantage: some powdered calcium
sulfide is mixed with collodion, diluted with ether, so as to
form a very thin paste; then, with a water-color brush, drops of
this paste are painted on blackened cardboard, so as to produce
stains several millimeters in diameter, close to each other. The
screen then presents the aspect of a spotted fabric. If, after
being exposed to light, it is examined in a dark room, and in
perfect silence, some of the spots will appear less luminous
than the others. Usually, some will not seem to be sharply
separated from their neighbors, but will form a sort of confused
nebula less visible than the rest. Now, if one speaks aloud...

[Missing text: I lost pp.80-81 of my photocopy -- ed.]

**(18)  How the Action of N Rays Should be Observed**

It is indispensable in these experiments to avoid all strain on
the eye, all effort, whether visual or for eye accommodation,
and in no way to try to fix the eye upon the luminous source,
whose variations in glow one wishes to ascertain. On the
contrary, one must, so to say, see the source without looking at
it, and even direct ones glance vaguely in a neighboring
direction. The observer must play an absolutely passive part,
under penalty of seeing nothing. Silence should be observed as
much as possible. Any smoke, and especially tobacco smoke, must
be carefully avoided, as being liable to perturb or even
entirely mask the effect of the N rays. When viewing the screen
or luminous object, no attempt at eye-accommodation should be
made. In fact, the observer should accustom himself to look at
the screen just as a painter, and in particular an
"impressionist" painter, would look at a landscape. To attain
this requires some practice, and is not an easy task. Some
people, in fact, never succeed.

*The End*

---

***Scientific American* (October 14, 1905), p. 299**

**"Photographic Records of the Action of
N-Rays"**

The much discussed problem of the existence of N rays could be
settled only by an objective demonstration of their effects. As
these rays exert no immediate action on photographic plates,
Prof. Blondlot some time ago endeavored to obtain indirect
photographic records, by taking a view of the same spark first
without N rays, and afterward with N rays. In the latter case a
more intense impression on the photographic plate was observed.
Opponents of the French scientist contended that the electric
sparks were not of sufficient constancy to warrant him drawing
any definite conclusions from these experiments. Prof. Blondlot
therefore continued his efforts in this direction, and in a
memoir published in a recent issue of the Revue Generale des
Sciences describes a few further experiments where every care
has been takes to avoid any uncertainty. These experiments
really demonstrate the objective existence of the radiations.
The process used was practically the same as that employed
previously, but for a telephone inserted in the secondary
circuit of the induction coil. The assistant, by keeping the
telephone receiver close to his ear, was in a position to check
the regularity of the spark throughout the duration of the
experiments. If the spark was extinguished owing to an excessive
distance of the points, the sound in the telephone was also
discontinued. If, on the contrary, the points touched each
other, the sound became much more intense. Any irregularities in
the spark might thus be detected, and if any were observed
during a photographic experiment, the photographs were rejected.

In a series of 35 experiments carried out with every care, 23
tests showed a most striking difference between the images
obtained with and without N rays, while 8 tests gave a rather
noticeable contrast, and 4 tests a contrast still visible though
less marked. All the plates did show the action of N rays, and
if the difference between the two photographic impression was
not always of the same intensity, this must be ascribed to the
impossibility of obtaining an absolutely exact regulation of the
small spark.

It is of great importance that exceedingly feeble sparks should
be employed, the brilliancy of which be little more than the
minimum luminous intensity capable of producing some impression
on the plate. Under these conditions a small variation in
luminous intensity will result in a great variation in the
intensity of the photographic image, while in the case of a
stronger illumination only a very small variation is obtained.

In the experiments referred to, the N rays were produced by a
Nernst lamp enclosed in a sheet-metal lantern. The N rays
traversed successively an aluminum foil constituting the front
wall of the latter, a pinewood plank 2 cm in thickness, another
aluminum foil, an aluminum lens, a zinc foil, a piece of
whitewood 2 cm in thickness, an aluminum foil, constituting an
electric screen to protect the spark, and finally the wall of
the pasteboard box inclosing the spark.

With all these experiments one second or more has been allowed
for the total duration of the exposure made without N rays so as
to make sure that this exposure was somewhat longer than the
other. Instead of simply taking two successive exposures with
and without N rays, another method, consisting in cross-wise
fractional photography, has been chosen in some instances. The
exposure with N rays was made either before or after the other,
and the experiments were varied in many other ways. Metal
screens were used so as to eliminate any disturbances likely to
be produced by electrical influence. Checking experiments were
made, from time to time either by withdrawing the moist paper or
by moistening it with salt water, when equivalent images were
obtained in each case.

These experiments seem to be free from any objection. While the
results practically agree with those obtained in connection with
former researches, the following interesting fact was discovered
incidentally:

If N rays be made to strike the primary spark of a Hertz
oscillator, the secondary spark will decrease in brilliancy.
This shows that N rays modify the electric phenomenon itself,
and the intimate alteration of the spark is doubtless the cause
for which the photographic experiments on the action of N rays
is used as illuminant, whereas no result is obtained with other
sources of light.

---



**"The Great N Ray Delusion"**

**by William Seabrook**

Excerpted from: "Random Walk through Physics"; condensed from
"Dr. Wood: Modern Wizard of the Laboratory", by William Seabrook
(Harcort Brace, 1941).

In the last autumn of 1903, Professor R. Blondlot, head of the
Department of Physics at the University of Nancy, member of the
French Academy, and widely known as an investigator, announced
the discovery of a new ray, which he called N ray, with
properties far transcending those of the x-rays. Reading of his
remarkable experiments, I attempted to repeat his observations,
but failed to confirm them after wasting a whole morning.
According to Blondlot, the rays were given off spontaneously by
many metals. A piece of paper, very feebly illuminated, could be
used as a detector, for, wonder of wonders, when the N rays fell
upon the eye they increased its ability to see objects in a
nearly dark room.

Fuel was added by a score of other investigators. Twelve papers
had appeared in the Comptes rendus before the year was out. A.
Charpentier, famous for his fantastic experiments on hypnotism,
claimed that N rays were given off by muscle, nerves, and the
brain, and his incredible claims were published in the Comptes,
sponsored by the great d'Arsonval, France's foremost authority
on electricity and magnetism.

Blondlot next announced that he had constructed a spectroscope
with aluminum lenses and a prism of the same metal, and found a
spectrum of lines separated by dark intervals, showing that
there were N rays of different refrangibility and wave length.
He measured the wavelengths. Jean Becquerel claimed that N rays
could be transmitted over a wire. By early summer, Blondlot had
published twenty papers, Charpentier twenty, and J. Becquerel
ten, all describing new properties and sources of the rays.

Scientists in all other countries were frankly skeptical, but
the French Academy stamped Blondlot's work with its approval by
awarding him the Lalande prize of 20000 francs and its gold
medal for the discovery of the N rays'.

In September (1904) I went to Cambridge for the meeting of the
British Association for the Advancement of Science. After the
meeting some of us got together for a discussion of what was to
be done about the N rays. Professor Rubens, of Berlin, was most
outspoken in his denunciation. He felt particularly aggrieved
because the Kaiser had commanded him to come to Potsdam and
demonstrate the rays. After wasting two weeks in vain attempts
to duplicate the Frenchman's experiments, he was greatly
embarrassed by having to confess to the Kaiser his failure.
Turning to me he said, Professor Wood, will you not go to Nancy
immediately and test the experiments that are going on there?'
Yes, yes', said all of the Englishmen, that's a good idea, go
ahead.' I suggested that Rubens go, as he was the chief victim,
but he said that Blondlot had been most polite in answering his
many letters asking for more detailed information, and it would
not look well if he undertook to expose him. Besides,' he added,
you are an American, and you Americans can do anything ...'

So I visited Nancy, meeting Blondlot by appointment at his
laboratory in the early evening. He spoke no English, and I
elected German as our means of communication, as I wanted him to
feel free to speak confidentially to his assistant.

He first showed me a card on which some circles had been
painted in luminous paint. He turned down the gas light and
called my attention to their increased luminosity, when the N
ray was turned on. I said I saw no change. He said that was
because my eyes were not sensitive enough, so that proved
nothing. I asked him if I could move an opaque lead screen in
and out of the path of the rays while he called out the
fluctuations of the screen. He was almost 100 percent wrong and
called out fluctuations when I made no movement at all, and that
proved a lot, but I held my tongue. He then showed me the dimly
lighted clock, and tried to convince me that he could see the
hands when he held a large flat file just above his eyes. I
asked if I could hold the file, for I had noticed a flat wooden
ruler on his desk, and remembered that wood was one of the few
substances that never emitted N rays. He agreed to this, and I
felt around in the dark for the ruler and held it in front of
his face. Oh, yes, he could see the hands perfectly. This also
proved something.

But the crucial and most exciting test was now to come.
Accompanied by the assistant, who was by this time casting
rather hostile glances at me, we went into the room where the
spectroscope with the aluminum lenses and prism were installed.
In place of an eyepiece, this instrument had a vertical thread,
painted with luminous paint, which could be moved along in the
region where the N ray spectrum was supposed to be turning a
wheel having graduations and numerals on its rim. Blondlot took
a seat in front of the instrument and slowly turned the wheel.
The thread was supposed to brighten as it crossed the invisible
lines of the N-ray spectrum. He read off the numbers on the
graduated scale for a number of the lines, by the light of a
small, darkroom red lantern. This experiment has convinced a
number of skeptical visitors, as he could repeat his
measurements in their presence, always getting the same numbers.

I asked him to repeat his measurements, and reached over in the
dark and lifted the aluminum prism from the spectroscope. He
turned the wheel again, reading off the same numbers as before.
I put the prims back before the lights were turned up, and
Blondlot told his assistant that his eyes were tired. The
assistant had evidently become suspicious, and asked Blondlot to
let him repeat the reading for me. Before he turned down the
light I had noticed that he placed the prism very exactly on its
little round support, with two of its corners exactly on the rim
of the metal disk. As soon as the light was lowered, I moved
over towards the prism, with audible footsteps, but I did not
touch the prism. The assistant commenced to turn the wheel, and
suddenly said hurriedly to Blondlot in French, I see nothing;
there is no spectrum. I think the American has made some
derangement.' Whereupon he immediately turned up the gas and
went over and examined the prism carefully. He glared at me, but
I gave no indication of my reactions. This ended the seance.

Next morning I sent off a letter to Nature giving a full
account of my findings, not, however, mentioning the
double-crossing incident at the end of the evening, and merely
locating the laboratory as `one in which most of the N-ray
experiments had been carried out'. La Revue scientifique,
France's weekly semipopular scientific journal started an
inquiry, asking French scientists to express their opinions as
to the reality of the N rays. About forty letters were
published, only a half dozen backing Blondlot. The most scathing
one by Le Bel said, `What a spectacle for French science when
one of its distinguished savants measures the position of the
spectrum lines, while the prism reposes in the pocket of his
American colleague!'

The Academy at its annual meeting in December, when the prize
and medal were presented, announced the award as given to
Blondlot for his life's work, taken as a whole.'

---

 [**http://physics.csufresno.edu/wassign/phys4a/hall/temp5/experience\_pitfalls.htm**](http://physics.csufresno.edu/wassign/phys4a/hall/temp5/experience_pitfalls.htm)


**"Fooling Students into not Fooling
Themselves"**

*Four activities designed to engage students
in the methods of science by showing how personal experience
is not always to be trusted.*

**by Raymond Hall** 

*Expectation Bias and Seeing Things*

Here is a short account of a famous instance of expectations
bias, or just plain jumping to conclusions. In 1903, during a
time of major discoveries of many new forms of radiation,
Professor Rene Blondlot of the University of Nancy reported the
discovery of a remarkable new radiation he labeled N-rays10. He
claimed these rays were emitted by all things except green wood
and some treated metals, and had similar penetrating properties
akin to X-rays. A number of other French scientists had
corroborated his findings by duplicating his experiments. In one
experimental arrangement, the N-rays were said to refract
through a metal prism, and that a spectrum of dark and light
N-ray bands could be cast. Instead of an eyepiece the
spectrometer had a vertical thread treated with luminous paint.
N-ray bands were detected by Blondlot, determining by eye the
faint glow of the string as an assistant called out angles and
rotated the prism through a set of intervals.

The journal Nature sent American physicist James Wood to
investigate the amazing claims of the N-ray experiments. Wood
was invited into Blondlots lab for a demonstration, and while
waiting in the dark for Blondlots eyes to adjust, Wood quietly
removed the metal prism from the apparatus. Although the prism
was in Woods pocket, thus completely disabling the apparatus,
Professor Blondlot nevertheless called out the presence and
absence of N-rays exactly where he had reported and expected
them to be (Ref. 11).

The detection mechanism of Blondlots experiment had an
unfortunately large subjective aspect, that of visually
distinguishing a very feeble illumination, literally on the
threshold of detection. Could Blondlots strong expectation to
see the string glow really manifest in his perception, so that
he really saw a glow when none were present? Many have come to
this conclusion.

In the case of Blondlot, perhaps the expectation came from his
considerable investment in his own hypothesis, or was reinforced
by his lab assistants not wanting to contradict their esteemed
professor. Whatever the case, the lesson for the students is
that his experimental procedure screamed out for the application
of a blinded test. If Blondlot had asked his assistant to do in
a controlled fashion what Wood had imposed on him, N-rays may
never have seen the printed page.

There are other instructive and entertaining incidents in the
annals of physics, one of which I highly recommend is the story
of Martin Fleischmann and Stanley Pons' announcement of cold
fusion in 1989.  The account as told in Robert Park's book
Voodoo Science13 gets to the very heart of the problem: signal
on the threshold of detection above noise, subversion of peer
review, lack of use of control samples (what is the result if
you do not use heavy water in your vessel?), and of course a
wide berth for expectation bias.

The human pitfall of expectation bias is sometimes referred to
as wishful thinking, and plays a role in the acceptance of many
questionable beliefs including N-rays, cold fusion, ancient
astronauts, claims of perpetual motion ("over unity") devices,
and many alternative healing claims, to name a few.

11. Robert W. Wood, "The N-rays", Nature 70, (1904) 530-531.

---

[**http://www.clpex.com/Articles/ObserverEffectsinForensicScience.htm&e=7388**](http://www.clpex.com/Articles/ObserverEffectsinForensicScience.htm&e=7388)

**"Reasons to Challenge Digital Fingerprint
Evidence"**

**California Law Review (January, 2002)**

Sir Isaac Newton failed to report absorption lines in the
prismatic solar spectrum, though they would have been clearly
visible with the apparatus he was using. The most likely
explanation for his failure to see them is that he held
theoretically based expectations that such phenomena should not
exist. Because he believed they did not exist, he failed to see
them, or at least to note their presence.

While Newton failed to see something that did exist, scientists
of the early twentieth century saw something that did not exist.
First reported by Rene Blondlot in 1903, "N-rays" appeared to
make reflected light more intense. So long as they were believed
to exist, the effects of N-rays were "observed" by many
scientists. Of course, once it was determined that N-rays did
not exist, their effects ceased to be observed.

---

**http://www.lcc.gatech.edu/~corse/2100/Chapter2.html**

Let us take another example, this time from the history of
science. At the turn of the century, Blondlot, a physicist from
Nancy, in France, made a major discovery like that of X-rays.3
Out of devotion to his city he called them N-rays'. For a few
years, N-rays had all sorts of theoretical developments and many
practical applications, curing diseases and putting Nancy on the
map of international science. A dissenter from the United
States, Robert W. Wood, did not believe Blondlot's papers even
though they were published in reputable journals~ and decided to
visit the laboratory. For a time Wood was confronted with
incontrovertible evidence in the laboratory at Nancy. Blondlot
stepped aside and let the N-rays inscribe themselves straight
onto a screen in front of Wood. This, however, was not enough to
get rid of Wood, who obstinately stayed in the lab asking for
more experiments and himself manipulating the N-ray detector. At
one point he even surreptitiously removed the aluminium prism
which was generating the N-rays. To his surprise, Blondlot on
the other side of the dimly lit room kept obtaining the same
result on his screen even though what was deemed the most
crucial element had been removed. The direct signatures made by
the N-rays on the screen were thus made by something else. The
unanimous support became a cacophony of dissent. By removing the
prism, Wood severed the solid links that attached Blondlot to
the N-rays. Wood's interpretation was that Blondlot so much
wished to discover rays(at a time when almost every lab in
Europe was christening new rays) that he unwittingly made up not
only the N-rays, but also the instrument to inscribe them. Like
the manager above, Wood realised that the coherent whole he was
presented with was an aggregate of many elements that could be
induced to go in many different directions. After Wood's action
(and that of other dissenters) no one 'saw' N-rays any more but
only smudges on photographic plates when Blondlot presented his
N-rays. Instead of enquiring about the place of N-rays in
physics, people started enquiring about the role of
auto-suggestion in experimentation! The new fact had been turned
into an artefact....

Wood, who did not believe in N-rays, also tried to shake the
connection between Blondlot and his rays. Unlike the former
dissenter he succeeded. To dislocate the black boxes assembled
by Blondlot, Wood did not have to confront the whole of physics,
only the whole of one laboratory....

It is crucial to grasp that these two adjectives ('objective',
'subjective') are relative to trials of strength in specific
settings. They cannot be used to qualify a spokesperson or the
things he or she is talking about once and for all. As we saw in
Chapter 1, each dissenter tries to transform a statement from
objective to subjective status, to transform, for instance, an
interest in N-rays inside physics into an interest in
self-suggestion in provincial laboratories.

---

[**http://www.cs.ucsd.edu/users/goguen/courses/275f00/Burke.html**](http://www.cs.ucsd.edu/users/goguen/courses/275f00/Burke.html)

**"Worlds Without End"**

**by** **James Burke**

Elsewhere in Europe Wilhelm Rontgen discovered X-rays in 1895,
and a year later Antoine Becquerel identified radioactivity. By
1900 alpha, beta and gamma rays had been found. More were
expected. In 1903 a distinguished physicist called Rene
Blondlot, who was a member of the French Academy of Sciences and
a senior figure at Nancy University, announced his discovery of
another ray. In honour of his city he called it the N-ray.

Blondlot had found the new form of radiation while looking at
the behaviour of polarised X-rays. He had seen that the new
rays, which penetrated aluminium, increased the brightness of an
electric spark. The rays were also refracted by a prism and it
was known that X-rays could not be refracted in this way. Since
the scientific community expected new rays to be found,
Blondlot's work immediately attracted dozens of young graduates
keen to make their name in this new field.

Within three years three hundred papers had been written on the
subject, and doctoral theses were being prepared. Not only did
the rays traverse material opaque to light, but,
extraordinarily, they were given off by the muscles of the human
body. Moreover, N-rays heightened perception and they were
produced by the human nervous system particularly during
intellectual exertion. Was there a relationship between the
mysterious N-rays and the psyche? In 1904 Blondlot was awarded
the prestigious Prix Lecomte by the Academy of Sciences.

The crucial stage in the experiment proving the existence of
N-rays was the brightening of the spark, which Blondlot always
insisted had to be feeble. The trouble was that nobody outside
the city of Nancy could see differences in the brightness. In
September 1904 an American Professor of Physics, R. W. Wood,
arrived in Nancy and Blondlot demonstrated the effect for him.
Wood, too, was unable to see changes in the spark. He had
previously noted that with the equipment currently available the
minimum natural variation to which any spark's brightness could
be controlled was as much as 25 per cent. Spark brightness was
obviously a dubious criterion of measurement. It was when
Blondlot used a prism to refract and split the N-rays so as to
show the spread of their wavelength that Wood decided to act.
While his French hosts were busy in the dark, Wood removed the
prism. The demonstrators continued to see the N-rays. Wood
published his story the same month. No more N-rays were
observed. The discipline collapsed as quickly as it had
appeared.

There was never any suggestion that Blondlot was a charlatan.
He and his colleagues were victims of the expectation that
N-rays would be discovered and when they built instruments to
see the rays, they saw them. For a short time this non-existent
phenomenon resisted the most stringent tests and methods known
to science.

---

[**http://www2.sfu.ca/psychology/groups/faculty/beyerstein/research/articles/02SciencevsPseudoscience.doc&e=7388**](http://www2.sfu.ca/psychology/groups/faculty/beyerstein/research/articles/02SciencevsPseudoscience.doc&e=7388)

**"Distinguishing Science From
Pseudo-Science"**

**by** **Barry L. Beyerstein**  **( Department of Psychology ~ Simon Fraser University )**

*Pseudoscience in Physics:*

**N-Rays.**  One of the best-known examples of esteemed
scientists acting like pseudoscientists is found in the career
of the French physicist, Rene Blondlot, around the turn of the
20th century.  On the heels of the discovery of X-rays by
the German, Roentgen, French scientists felt pressured to catch
up by scoring a breakthrough of their own.  Blondlot, who
already had several important discoveries to his name, believed
he had observed yet another form of radiation which he named
"N-rays" in honour of his institution, the University of
Nancy.  Blondlot's "observations" were eventually shown by
the American physicist, Robert Wood to have been the joint
result of wishful thinking and some subtle distortions that
normally occur in visual perception.  These visual
aberrations tend to be ignored under ordinary viewing conditions
but they stood out against the backgrounds of Blondlot's viewing
apparatus.  The discoverers of N-Rays had allowed their
hopes and expectations to colour their observations. 
Unfortunately, they had failed to include a simple experimental
control that would have saved them much embarrassment. 
Wood made his point by surreptitiously inserting this control
condition into a demonstration provided for him during a visit
to Blondlot?s laboratory.  It is interesting to note that
there had been a number of independent "replications" of N-rays
by respected laboratories; the fact that some others had failed
to find the new radiation had piqued Wood?s interest.  His
expose highlights the need for mechanized recording of data,
wherever possible, to minimize the all too human tendency to
?see? what we are predisposed to see.  It is this tendency
to find what we expect that makes tight experimental controls,
independent replication, and careful statistical analyses an
absolute necessity in all research.  If honest,
well-trained scientists occasionally fall prey to such foibles,
it is not hard to understand why pseudoscientists are such
frequent victims.

---

[**http://www.navi.net/~rsc/physics/wallace/farce.txt**](http://www.navi.net/%7Ersc/physics/wallace/farce.txt)

**"Pathological Physics"**

 There is a very interesting article published in the
October 1989 issue of *Physics Today* [86]  The
article is titled "PATHOLOGICAL SCIENCE" and the abstract reads:
"Certain symptoms seen in studies of 'N rays' and other elusive
phenomena characterize 'the science of things that aren't so. '
"

The introduction to the article starts:

"Irving Langmuir spent many productive years pursuing
Nobel-caliber research (see the photo on the opposite page).
Over the years, he also explored the subject of what he called
"pathological science."  Although he never published his
investigations in this area, on 18 December 1953 at General
Electric's Knolls Atomic Power Laboratory, he gave a colloquium
on the subject that will long be remembered by those in his
audience. This talk was a colorful account of a particular kind
of pitfall into which scientists may stumble.

Langmuir begins his presentation with:

The thing started in this way.  On 23 April 1929,
Professor Bergen Davis from Columbia University came up and gave
a colloquium in this Laboratory, in the old building, and it was
very interesting....

Langmuir then gives the details of the Davis and Barnes
controversial experiment that produced a beam of alpha rays from
polonium in a vacuum tube with a hot cathode electron emitter
and a microscope for counting alpha induced scintillations on a
zinc sulfide screen.  Then Langmuir described the results
of a visit he and a colleague, C. W. Hewlett, made to Davis's
laboratory at Columbia University.  With regard to the
experiment Langmuir states:

And then I played a dirty trick. I wrote out on a card of paper
ten different sequences of V and 0. I meant to put on a certain
voltage and then take it off again.  Later I realized that
[trick wouldn't quite work] because when Hull took off the
voltage, he sat back in his chair??there was nothing to regulate
at zero so he didn't. Well, of course, Barnes saw him whenever
he sat back in his chair. Although the light wasn't very bright,
he could see whether [Hull] was sitting back in his chair or
not, so he knew the voltage wasn't on, and the result was that
he got a corresponding result. So later I whispered, "Don't let
him know that you're not reading," and I asked him to change the
voltage from 325 down to 320 so he'd have something to regulate.
I said, "Regulate it just as carefully as if you were sitting on
a peak."  So he played the part from that time on, and from
that time on Barnes's readings had nothing whatever to do with
the voltages that were applied. Whether the voltage was at one
value or another didn't make the slightest difference. After
that he took 12 readings, of which about half were right and the
other half were wrong, which was about what you would expect out
of two sets of values. I said: "You're through.  You're not
measuring anything at all.  You never have measured
anything at all."

"Well," he said, "the tube was gassy. The temperature has
changed and therefore the nickel plates must have deformed
themselves so that the electrodes are no longer lined up
properly."

"Well," I said, "isn't this the tube in which Davis said he got
the same results when the filament was turned off completely?"

"Oh, yes," he said, "but we always made blanks to check
ourselves, with and without the voltage on."

He immediately -- without giving any thought to it -- he
immediately had an excuse.  He had a reason for not paying
any attention to any wrong results.  It just was built into
him. He just had worked that way all along and always would.
There is no question but [that] he is honest: He believed these
things, absolutely....

At the end of that section, Langmuir states:

To me, [it's] extremely interesting that men, perfectly honest,
enthusiastic over their work, can so completely fool
themselves.  Now what was it about that work that made it
so easy for them to do that?  Well, I began thinking of
other things. I had seen R. W. Wood and told him about this
phenomenon because he's a good experimenter and doesn't make
such mistakes himself very often -- if at all. [Wood was a
physicist from Johns Hopkins University.] And he told me about
the N rays that he had an experience with back in 1904.  So
I looked up the data on N rays.[87]

Then Langmuir gave a detailed account of N rays, and how they
were discovered in 1903 by a respected French physicist, Rene
Prosper Blondlot, at the University of Nancy. The N-rays were
supposed to be generated by a hot wire inside an iron tube that
has an 1/8 inch aluminum window in it, and the rays are detected
by a calcium sulfide screen which gave out a very faint glow in
a dark room.  One of the experiments involved a large prism
of aluminum with a 60 degree angle.  Wood visited
Blondlot's lab and Langmuir recounts the following trick Wood
played on Blondlot:

Well, Wood asked him to repeat some of these measurements,
which he was only too glad to do. But in the meantime, the room,
being very dark, R. W. Wood put the prism in his pocket and the
results checked perfectly with what [Blondlot] had before. Well,
Wood rather cruelly published that.[88]  And that was the
end of Blondlot...

---

**Cleveland Public Library.**   
[**http://js-catalog.cpl.org:60100/MARION?S=N+RAYS**](http://js-catalog.cpl.org:60100/MARION?S=N+RAYS)

**Blondlot, R. (Rene), 1849-1930.**

"N" rays: a collection of papers communicated to the Academy of
sciences, with additional notes and instructions for the
construction of phosphorescent screens; by R. Blondlot ... Tr.
by J. Garcin ... With phosphorescent screen and other
illustrations.   
London, New York and Bombay, Longmans, Green, and co., 1905.

---

[**http://www.williamjames.com/Science/ERR.htm**](http://www.williamjames.com/Science/ERR.htm)



**"To Err is Human"**

**William James**

The story of the "discovery" of N-rays in France in 1903
reveals how physics, the "hardest" of the sciences, could be led
astray by subjective evaluation. This "new" form of X-rays
supposedly could be detected by the human eye in a nearly
darkened room. The best physical scientists in France accepted
this breakthrough. Within a year of its original "discovery" by
Professor R. Blondlot, the French Academy of Science had
published nearly 100 papers on the subject.

However, in 1904 the American physicist Robert Wood visited
Blondlot's laboratory and discovered, by secretly changing a
series of experimental conditions, that Blondlot continued to
see the N-rays under circumstances that Blondlot claimed would
prevent their occurrence. When Wood published his findings, it
became clear that the French scientists had believed so strongly
in N-rays that they had virtually hallucinated their existence.
Good research can disconfirm theories, subjective judgment
rarely does.

---

[**http://www.palmyra.demon.co.uk/feedback/st.htm**](http://www.palmyra.demon.co.uk/feedback/st.htm)

Simon Teague comments:

There is little, if anything, to differentiate McCarthyism and
Stalinism when it come to such things as purges and informers,
all for "the good of the state", but it does not follow from
that, that any system which is shown to be flawed should be
discarded in its entirety: like a scientific theory open to
scrutiny, it should be tested and, if found wanting, revised and
updated - unless it is like Blondlot's N-rays, which was 
thrown away.

---

[**http://www.hyle.org**](http://www.hyle.org)   
***HYLE--International Journal for Philosophy of Chemistry*,
Vol. 8, No.1 (2002), pp. 5-20**

**N-Rays**

**by** **Henry H. Bauer**

N-rays have been referred to innumerable times, but the best
scholarly discussions are by Derek de Solla Price (1975) and
Mary Joe Nye (1980).

Rene Blondlot, in France, at the University of Nancy (hence
N-rays), announced his discovery of N-rays in 1903: a new form
of radiation, emitted by both living and inanimate bodies, able
to penetrate aluminum but not lead, able to be refracted by
aluminum prisms as light is refracted by glass. For several
years, N-rays were studied by scores of scientists in France and
hundreds of papers were published. Yet scientists in other
countries were not able to reproduce the radiation. An American
physicist, Robert Wood, observed the experiments in Blondlots
lab: in darkness, visual observation was used to detect on
measuring scales the spots of light that N-rays produced.
Surreptitiously in the darkened room, Wood removed the aluminum
prism. The measurements continued to be read out as before.
Evidently optical illusion was causing spots of light to be
imagined at expected values along the scales. This demonstration
convinced almost all the scientific community that N-rays do not
exist; but Blondlot and a few others persisted in their belief
that N-rays were real.

So presumably what was pathological here was a reliance on
visual observation under conditions -- a darkened room -- where
optical illusions readily occur. (One modern test for glaucoma
is to note over what field of view one can detect flashes of
light on a dark background. Anyone who has taken such a test
knows that one sees some number of flashes that are not
actually there.) But Blondlot was a distinguished member of the
French scientific establishment. He had been particularly
praised for showing that X-rays moved at the speed of light
which he had established by the same method of visual
observation, in that case variations in the apparent intensity
of electric sparks. Blondlot was therefore very unfortunate; but
how can he be blamed for continuing to use a technique that had
been so successful? "The curious error of N-rays is much more a
sort of mass hallucination, proceeding from an entirely
reasonable beginning" (Price 1975, p. 159).

Moreover, the facts Blondlot reported were confirmed by a
number of his fellow scientists, not only in his laboratory but
also elsewhere in France; which gave Blondlot good reason to
think his discovery a genuine one. And early in the 20th
century, Blondlot was far from alone in looking for new types of
radiation. X-rays and radioactivity had been discovered just a
decade earlier, and some years before that Hertz had discovered
radio waves.

If pathological science is to be regarded as scientific
misconduct, then there would need to be some indication that
there had been willful deception, or at least quite egregious
incompetence. The record does not support indictment of Blondlot
on either of those scores. In point of fact, if anyone behaved
unethically during this episode, it would seem to be Robert
Wood, who deliberately and surreptitiously interfered with the
experiments in order to deceive the experimenters; yet I know of
no discussion of the case that does anything but praise Wood for
his demonstration that N-rays are not real phenomena.

---

[**http://www.marshall.org/article.php?id=172&print=1**](http://www.marshall.org/article.php?id=172&print=1)

**"Who Speaks For Science In Court?"**

**by** **Peter Huber**   
May 3, 1993

There's the famous episode of the N-rays in France at the turn
of the century. It is the great classic in bad science -- really
intriguing. It's sort of horribly fascinating to watch a Rene
Blondlot, who had been a reasonably good scientist in his time,
claim he had discovered these N-rays. The evidence mounted that
there was no such thing as an N-ray -- he was, in fact,
observing nothing. But year after year he developed more
elaborate and comically sad reasons why N-rays were nevertheless
there but only he, and nobody else, could see them.

---

[**http://www.worldhistory.com/wiki/N/N-ray.htm**](http://www.worldhistory.com/wiki/N/N-ray.htm)

**Rene-Prosper Blondlot**

The so-called N rays (or N-rays) were a phenomenon described by
French scientist Rene-Prosper Blondlot, subsequently shown to be
illusory.

In 1903, Blondlot, a distinguished physicist working at the
University of Nancy, perceived changes in the brightness of an
electric spark in a spark gap which he attributed to a novel
form of radiation, naming it the N-ray, for the University of
Nancy. Blondlot, Augustin Charpontier, Arsene d'Arsonval and
many others claimed to be able to detect rays emanating from
most substances, including the human body. Physicists Gustave le
Bon and P. Audollet and spiritualist Carl Hunter even claimed
the discovery as their own, leading to a commission of the
Academie des sciences to decide priority.

The "discovery" excited international interest and many
physicists worked to replicate the effects. However, notable
physicists Lord Kelvin, William Crookes, Otto Lummer and
Heinrich Rubens all failed to do so. Following his own failure,
US physicist Robert W. Wood was prevailed upon to travel to
France to investigate further. His thorough investigations,
published in the September 29 1904 edition of Nature, showed
that these were a purely subjective phenomenon, with the
scientists involved having recorded data that matched their
expectations. The incident is used as a cautionary tale among
scientists on the dangers of error introduced by experimenter
bias.

N rays were cited as an example of pathological science by
Irving Langmuir.   
External links and references:

[**http://skepdic.com/blondlot.html**](http://skepdic.com/blondlot.html)
and references therein; Klotz, I M (year?) The N-ray affair,
Scientific American

---

[**http://www.sciencedaily.com/encyclopedia/rene\_prosper\_blondlot**](http://www.sciencedaily.com/encyclopedia/rene_prosper_blondlot)

Rene-Prosper Blondlot (July 3, 1849 - November 24, 1930) was a
French physicist, best remembered for his mistaken
identification of N rays, a phenomenon that subseqeuntly proved
to be illusory. Born in Nancy, France, he spent most of his
early years there, teaching physics at the University, being
awarded three prestigious prizes of the Academie des Sciences
for his experimental work on the consequences of Maxwell's
theory of electromagnetism. In order to demonstrate, in
collaboration with Ernest Bichat, that a Kerr cell responds to
an applied electric field in a few 10s of microseconds, he
adapted the rotating-mirror method that Leon Foucault had
applied to measure the speed of light. He further developed the
rotating mirror to measure the speed of electricity in a
conductor, photographing the sparks emitted from two conductors,
one 1.8 km longer than the other and measuring the relative
displacement of their images. He thus estabished that the speed
of electricity in a conductor is very close to that of light. In
1903, Blondlot announced that he had discovered N rays, a new
species of radiation. The "discovery" attracted much attention
over the following year until Robert W. Wood showed that the
phenomena were purely subjective with no physical origin.
Blondlot lived the rest of his life in comparative obscurity in
Nancy where he died.

---

[**http://www.o4r.org/pf\_v5n1/Hoaxes.htm**](http://www.o4r.org/pf_v5n1/Hoaxes.htm)

**"Benign Hoaxes -- Wake-up Calls to the
Gullible"**

**by**

**Jeanine DeNoma**

Based on a talk given by Dr, Barry Beyerstein at the Skeptics
Toolbox in Eugene in August of 1998.

**Rene Blondlots N-Rays**

One of sciences most famous hoaxes revealed that a newly
discovered form of electromagnetic radiation was in fact a
figment of its discoverer and his followers imaginations.

In 1903 physicist Rene Blondlot, a member of French Academy of
Sciences and an expert in electromagnetic radiation, published
his discovery of N-rays in the scientific journal Comptes
rendus. By the following year, more than 50 papers appeared
describing the curious properties and sources of N-rays.

N-rays had quite remarkable properties. They passed through
materials opaque to visible light, such as metal, wood and
paper, yet were blocked by water, which transmits light.
Blondlot used an aluminum prism to bend the N-rays and
water-soaked cardboard to block them. N-rays were found to
emanate from the sun and the typical gas burner, but not from
Bunsen burners. Augustin Charpentier, a medical physicist, found
that the human body emitted N-rays, especially the nerve and
muscle cells. He suggested they could be used in medicine to
detect the outlines of organs.

Other researchers challenged Blondlots right to be noted as
the discoverer of this new ray. Gustave le Bon, also a
physicist, wrote Blondlot to say he had discovered a similar
radiation seven years earlier. P. Audollet claimed that he, not
Charpentier, had been the first to find N-rays were emitted from
the body; and a spiritualist, Carl Huter, challenged both
Audollet and Charpentier for this credit.

Several laboratories outside of France, however, reported
difficulty detecting this new radiation. One physicist having
trouble was Robert Wood, a well-respected researcher in the
field of optics and electromagnetic radiation from Johns Hopkins
University. The British journal Nature sent Wood to France to
observe Blondlots methods. Wood was an interesting choice
because not only was he a noted physicist, he was also
well-known as a showman and prankster with a wide range of
interests. He had investigated spiritualists for fraud and
pursued an interest in using scientific methodologies for
solving crimes.

In the first experiment Wood observed, N-rays concentrated by
an aluminum lens were said to brighten an electric spark if a
hand was passed between the spark and the N-ray source. Wood
said could not see any increase in brightness, but Blondlot
attributed this to Woods lack of visual sensitivity. Wood
noted, however, that Blondlot couldnt correctly identify when
Woods hand was or was not present.

In Blondlots second demonstration, a photographic plate,
rather than the eye, was used to detect the increased
brightness. Unfortunately, Wood noted, the conditions under
which the plate was exposed were subject to "many sources of
error." The most serious being that the plate was moved back and
forth by hand for five-second exposures under first one
condition and then the other. Wood pointed out that unconscious
bias by the experimenter, who knew the conditions, could account
for the increased exposure clearly visible on the plate
subjected to the intensified N-rays. He suggested a series of
blinded experiments which would eliminate this source of error.
Blondlot dismissed such precautions as unnecessary.

In the third and most famous experiment, Wood was shown how an
aluminum prism bent and spread the N-rays into a spectrum.
Again, this was detected visually, this time by an increase in
brilliancy at certain points along a strip of phosphorescent
paint. Wood made a conclusive judgement about the reliability of
Blondlots observations by surreptitiously removing the prism.
Blondlot, not realizing the prism had been removed, continued to
report seeing the expected changes.

Wood writes, "I was unable to see any change whatever in the
brilliancy of the phosphorescent line...and I subsequently found
that the removal of the prism (we were in a dark room) did not
seem to interfere in any way with the location of the maxima and
minima in the deviated (!) ray bundle".

After a couple lesser tests yielding similar results, Wood left
the lab convinced that N-rays were "purely imaginary". Woods
report was published in Nature on September 29, 1904. Wood
carefully avoided naming Blondlot in his report, although it was
widely known by researchers in the field whose lab Wood had
visited.

Following its publication Blondlot was encouraged to conduct a
definitive test to settle the N-ray issue once and for all.
Blondlot did not respond to these requests until 1906 when he
wrote,"Permit me to decline totally your proposition to
cooperate in this simplistic experiment; the phenomena are much
too delicate for that. Let each one form his personal opinion
about N-rays, either from his own experiments or from those of
others in whom he has confidence". Blondlot continued his work
on N-rays until his retirement in 1909.

When Blondlot published his discovery of N-rays, the X-ray,
alpha and beta "rays", and gamma rays had all recently been
discovered. Scientists were primed to expect more discoveries
and, initially, most embraced N-rays with excitement. Skepticism
set in only when other labs were unable to repeat Blondlots
observations. Although many French scientists helped debunk
N-rays, a small group clung to their belief in the authenticity
of N-rays long after the evidence warranted. Personal attachment
and French nationalism seemed to motivate this belief. Some
French defenders were known to claim that only Latins had the
intellectual and visual "sensitivities" to detect N-rays.

---

[**http://www.burgy.50megs.com/nrays.htm**](http://www.burgy.50megs.com/nrays.htm)

N-RAYS.HTM To address the claim by Joseph that when science
goes wrong that the scientistists must have committed fraud, I
intend to show an instance in which the explanation was not
fraud as much as self-deception:

---

[**http://www.skeptic.com/01.1.randi-paranormal.html**](http://www.skeptic.com/01.1.randi-paranormal.html)

"I want to close this presentation with some parallel examples
of scientific claims that turned out to be so much nonsense.
Let's go back to 1903 in France. You may have heard of this, if
not it really is something you should look up. A prominent
scientist - a physicist named Rene Blondlot - startled the world
of science with his announcement of the discovery of N-rays. A
very well respected man who had won many prizes in science and
justifiably so, he was doing experiments by today's standards
that were very simple - such as finding the speed of electricity
in a conductor. It sounds easy today, but in those days it was a
very sophisticated experiment and not all that easily done.
Blondlot was in his 70s at the time when he discovered N-rays,
named after the town of Nancy, where he was head of the
Department of Physics at the University of Nancy."

"What were N-rays? N-rays were allegedly radiation exhibiting
impossible properties emitted by all substances with the
exception of green wood (wood not dried out) and anesthetized
metal. (Metal that had been dipped in ether or cholorophorm did
not give out N-rays!) Within a matter of six to eight months of
the announced discovery of N-rays, 30 papers had come in from
all over Europe confirming the existence of N- rays. Reports
were published in journals despite the fact that there were many
laboratories reporting failure after failure in replicating the
results. Such acceptance was understandable considering that
X-rays, which also exhibited unsuspected properties, were by
then firmly established."

"What Blondlot had was a basic spectroscope with a prism (not
glass, but aluminum) on the inside, and a thread. The narrow
stream of N-rays was refracted through the prism and coming out
produced a spectrum on a field. The N-rays were reported to be
invisible, except when viewed when they hit a treated thread
(for example, treated with calcium sulfide). They moved the
thread across the gap where the N-rays came through and when it
was illuminated that was reported as the detection of the N-
rays."

"Before long N-rays were established as factual. Nature
magazine was skeptical of the N-rays since laboratories in
England and Germany were unable to find them. (Germany had just
discovered X-rays the decade before and the French were annoyed
that they didn't have a ray.) Nature sent an American physicist
named Robert W. Wood from Johns Hopkins University to
investigate. Now, I've been accused of skulduggery in my time,
but what Wood did was brilliant. When no one was looking he
removed the prism from the N-ray detection device and put it in
his pocket. Without the prism the machine could not possibly
work because it was dependent on the refraction of N-rays by the
aluminium-treated prism. Yet, when the assistant conducted the
next experiment he found N- rays! He swore they were there."

"When the experiment was over Wood knew it was really over. He
was prepared to make his report, and when he went to replace the
prism back in the machine, one of the other assistants saw him
do this and thought he was actually removing it, and he decided
to show Wood up. Thinking Wood had removed the prism (when he
had actually put it back), he set up the experiment, could find
no lines, and opened the box to show that the prism was not
there and to his dismay, there it was! The whole incident blew
up. Papers were withdrawn, those that were in the mail were
retracted, and N-rays disappeared from the scene."

"How did this happen? How did over 30 papers get published? Not
because the scientists who wrote the papers were stupid. Not
because they were lying. But because they were deceiving
themselves.

---

[**http://seercom.com/bcs/resources/skeptopaedia/n/nrays.html**](http://seercom.com/bcs/resources/skeptopaedia/n/nrays.html)

Dr. Blondlot was a French physicist who, in 1903, was convinced
he had discovered a new type of ray, similar to X-rays. He named
them N-rays after his home town of Nancy, where he worked in the
university of the same name. He claimed that these rays were
emitted by every material, except green wood, and believed he
could generate large amounts of N rays by heating a wire and
refracting the combination of rays through an aluminum prism,
enclosed in the apparatus. The rays could be detected by
swinging a metal filament up and down across the invisible
spectrum until it glowed slightly. This glow could not be
detected by instruments, but required a human's experience to
confirm a positive result. Other scientists failed to repeat the
experiment.

*Debunking*

Well, things went from bad to worse as Blondlot hypothesized
that Germanic and American physiology was not as sensitive as
latins like himself and his Italian assistant, who found no
trouble detecting the rays, and Nature magazine dispatched Dr.
Robert Wood from Johns Hopkins University to observe Blondlot's
technique. During a pre-demonstration examination of the
instrument, Wood secretly removed the prism. Blondlot and his
assistants proceeded to spend several hours repeatedly finding
N-rays.

Satisfied that the rays were a delusion, Wood was caught
replacing the prism, although he managed to place it inside the
instrument. Wood picked up a second prism from its storage below
the instrument and pretended to have removed the original.
Blondlot, thinking the prism was now removed, demonstrated how
its absence generated negative results by failing to find the
rays for several tries. The original prism, of course, was back
inside the instrument. Several of the visiting scientists had
been informed of the prism's removal earlier and now knew of its
replacement. The results had obviously been entirely in
Blondlot's imagination, and he was very embarassed when all was
revealed.

*Lesson learned?*

Generally, scientists prefer to have several things in place
for an experiment to have high confidence: falsifiability,
repeatability, independant verification, control groups, and
double-blindedness. Other factors are important, but failure of
these four are problematic. The N-rays ran into trouble almost
immediately when only French laboratories could repeat the
experiment, complicating independant verification. The
experiment was falsifiable and repeatable, but it was certainly
not double-blinded: the observer simply had to wave the filament
around until he believed he felt a heat increase or saw a glow,
but he knew in advance the ray was there somewhere, it was
simply a matter of reinterpreting natural variations in
perception of light and heat as evidence for their effects on
the filament.

What I want to impress on readers is that neither intelligence
nor education is protection from deception or self-deception: we
can only avoid these types of problems in our lives by being
aware of our own mental limitations, since not everybody is like
Dr. Blondlot and accidentally making false claims: some people
do it on purpose to our disadvantage. Awareness of this is the
purpose of skepticism.

---

[**http://www.shodor.org/~aren/forensic/observation/perception.html**](http://www.shodor.org/%7Earen/forensic/observation/perception.html)

**"Perceptual Fallacies"**

The Blondlot Case and N-rays - famous case in which scientist
Rene Blondlot announced the discovery of N-rays, which could be
detected by the human eye and were emitted by metals. They
apparently increased the brightness. Blondlot claimed that this
type of radiation was blocked by lead. Scientists could not
reproduce his results because the experiments were entirely
subjective. Another scientist named Wood challenged Blondlot
while participating in a test of N-rays. He told Blondlot that a
lead sheet was in place when it was not, and Blondlot claimed to
see the rays. Wood then placed the lead sheet in front of the
source of N-rays and Blondlot claimed to see the N-rays.
Blondlot's observations depended entirely on his beliefs, and
were not correlated to when the sheet was actually in place.

---

[**http://skepdic.com/blondlot.html**](http://skepdic.com/blondlot.html)



**"The Skeptic's Dictionary"**

**Robert Todd Carroll**

Rene Prosper Blondlot (1849-1930) was a French physicist who
claimed to have discovered a new type of radiation, shortly
after Roentgen had discovered X-rays. He called it the N-ray,
after Nancy, the name of the town and the university where he
lived and worked. Blondlot was trying to polarize X-rays when he
claimed  to have discovered his new form of 
radiation. Dozens of other scientists confirmed the existence of
N-rays in their own laboratories. However, N-rays don't exist.
How could so many scientists be wrong? They deceived themselves
into thinking they were seeing something when in fact they were
not. They  saw what they wanted to see with their
instruments, not what was actually there (or, in this case, what
was not there).

The story of  Blondlot is a story of self-deception among
scientists. Because many people have the misguided notion that
science should be infallible and a fount of absolutely certain
truths, they look at the Blondlot episode  as a vindication
of their excessive skepticism towards science. They relish
accounts such as the one regarding Blondlot and the phantom
N-rays because it is a story of a famous scientist making a
great error. However, if one properly understands science and
scientists, the Blondlot episode indicates little more than the
fallibility of scientists and the self-correcting nature of
science.

Blondlot claimed that N-rays exhibit impossible properties and
yet are emitted by all substances except green wood and certain
treated metals. In 1903, Blondlot claimed he had generated
N-rays using a hot wire inside an iron tube. The rays were
detected by a calcium sulfide thread that glowed slightly in the
dark when the rays were refracted through a 60-degree angle
prism of aluminum. According to Blondlot, a narrow stream of
N-rays was refracted through the prism and produced a spectrum
on a field. The N-rays were reported to be invisible, except
when viewed as they hit the treated thread. Blondlot moved the
thread across the gap where the N-rays were thought to come
through and when the thread was illuminated it was said to be
due to N-rays.

Nature magazine was skeptical of Blondlot's claims because
laboratories in England and Germany had not been able to
replicate the Frenchman's results. Nature sent American
physicist Robert W. Wood of Johns Hopkins University to
investigate Blondlot's discovery. Wood suspected that N-rays
were a delusion. To demonstrate such, he removed the prism from
the N-ray detection device, unbeknownst to Blondlot or his
assistant. Without the prism, the machine couldn't work. Yet,
when Blondlot's assistant conducted the next experiment he found
N-rays. Wood then tried to surreptitiously replace the prism but
the assistant saw him and thought he was removing the prism. The
next time he tried the experiment, the assistant swore he could
not see any N-rays. But he should have, since the equipment was
in full working order.

According to Martin Gardner, Wood's exposure of Blondlot led to
the French scientist's madness and death (Gardner, 345 n.1). But
were those who verified Blondlot's N-ray experiments stupid or
incompetent? Not necessarily, since the issue isn't one of
intelligence or competence, but of the psychology of perception.
Blondlot and his followers suffered "from self-induced visual
hallucinations" (ibid.).

What is the lesson from the Blondlot episode? James Randi
writes:

 ...science does not always learn from these mistakes.
Visiting Nancy recently and speaking on the subject of
pseudoscience, I discussed this example and though I was in the
city that gave the name to N-rays, no one in the audience had
ever heard of them, or of Blondlot, not even the professors from
the University of Nancy!  --James Randi at Cal Tech

---

[**http://www.geocities.com/Area51/Chamber/1922/8030701t.html**](http://www.geocities.com/Area51/Chamber/1922/8030701t.html)

*PARADIGMA ONLINE ~* MARCH 9, 1998 (ARTICLE NO. 0018)

**"Paradigm Builder: N Rays"**

**by** **Ian Hawkins**

Rays that never were: a form of radiation discovered in 1903
that affects light sources and the human mind.

*Rene Blondlot's N-Rays*

In 1903, Rene-Prosper Blondlot was studying the polarization of
X-rays, a new form of radiation recently "discovered" by a
German Scientist. He was using a hot platinum filament enclosed
in an iron tube. A thin aluminum window allowed radiation to
escape. He found that radiation escaping his apparatus increased
the luminosity of a nearby gas flame. Further investigation
showed that the radiation caused a dimly illuminated screen
painted with calcium sulfide to brighten visibly. He named the
new radiation "N rays" for Nancy, the name of his town and the
university he worked at.

Dozens of other Scientists confirmed the existence of N rays.
Over 300 papers were published on the subject over the next
three years. Aluminum lenses and prisms were used to focus N
rays, which were stopped by thin folds of iron. Most things were
found to emit N rays: iron, most metals, even human bodies. A
brick wrapped in black paper and left in the sunshine became an
intense, long-life emitter of N rays, although two bricks
produced the same amount of radiation as a single brick.
Interestingly, only specially treated metals and wood did not
emit N rays. Wood, in fact, absorbed N rays.

*Inexplicable and Astounding Properties*

N rays themselves, like X rays, are not perceivable to the
unaided eye. Most experiments used a screen painted with calcium
sulfide to visualize the rays (the CaS would glow ever so
slightly). Through these experiments, N rays were found to have
a number of peculiar effects. They enhanced vision especially in
dimly lit areas. When focused on a flame or spark, the light
source glowed brighter. Loud noises made them dissipate while
heat made them more effective. They even had a documented effect
on the human brain!

The most tantalizing property of their complex structure was
that they retained a level of exactness through wide openings
not seen with normal radiation, such as visible light or X rays.
For instance, a 1/8 inch hole in a pin-hole camera would cause
the resulting image to be blurred by about 1/8 of an inch all
over. However, N rays passing though openings and prisms
separated into spectra with much greater resolution than would
be expected.

*Prologue*

The beginning of the century marked a crack-down on
"unauthorized science" by the Technocracy. The American
Scientist Wood was sent to France to unravel N rays and tear
them, ripping and screaming, from the scientific paradigm. Some
say that the choise of executioners shows how warped the humor
of our once-comrades is. Wood claimed that Blondlot and his
assistant saw what was not there and that the experiments worked
even when Wood removed essential equipment. He even claimed
that, at one point, the assistant could not see the effects of
the rays when the apparatus was in working condition. He
blatantly suggested that the assistant was lying and that
Blondlot was deceived. Wood's debunking (*Nature,* 1904)
led to Blondlot's madness and death. Papers on N rays were
published after 1904, but they quickly trickled to nothingness.
This is one of the many tragedies that lead to the entire
defection of the Electrodyne Engineer Convention to the
Traditions.

---