Francis E. Nipher: Electro-Gravitic Experiments (4 articles)

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**Prof. Francis E. NIPHER**

**Electro-Gravitic
Experiments**

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**[*NY Times*
(19 Sept. 1917)](#1)**  **[*Electrical Experimenter* (March 1918)](#2)**
 **[*Trans. Acad. Sci. St. Louis* XXIII (4):
173-176(July 28,1916)](#3)**  **[*Trans. Acad. Sci. of St. Louis* XXIII
(4): 177-193 (July 28, 1916)](#4)**  **[*Trans. Acad. Sci. of St. Louis* XXVII:
383-387 (March 2, 1920)](#5)**

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***New
York Times* (19 September 1917)**

**"Professor
Tells
of
Electrical Tests Turning Attraction Into Repulsion."**

A new theory as to
gravitation will be announced soon before the St. Louis
Academy of Sciences by Professor Francis E. Nipper, retired
head of the Department of Physics of Washington University.

"It will be shown that
gravitational attraction between masses of matter not only has
been diminished into zero, but has been converted into
repulsion which is more than twice as great as normal
attraction."

*New Gravitation Theory ~*

Professor Nipper made his
experiments with bodies suspended horizontally toward each
other. By introducing electricity into the atmosphere he
converted normal attraction into repulsion.

"If electricity can alter
the gravitational attraction of the bodies used in my
experiments," he said, "the same force can alter the earth's
attraction. If the negative electricity could be drawn from
the earth's surface, gravitational attraction suddenly would
cease and the cohesion of the earth's surface would be
disastrously affected."

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***Electrical
Experimenter* (March 1918)**

**"Can Electricity
Destroy Gravitation?"**

Is it possible to nullify,
and further to even reverse, the effect of gravity by
electricity? This scientific conundrum seems about to be
solved, at least to a certain extent. To begin with, everybody
is familiar with that law of physics which states that "all
particles of matter attract each other with a force which is
greater the nearer the particles are together", and to be
still more definite, Newton's law says that bodies behave as
if every particle of matter attracted every other particle
with a force that is proportional to the product of their
masses and inversely proportional to the square of the
distance between them. It is the gravitational attraction
between the earth and the bodies upon it which causes the
latter to have weight.

This fact is often lost
sight of and should be well understood by every student. To
make the matter more clear let us imagine that a man's body is
(as by flying, jumping, diving from a high point, etc.) for
the moment separated from the surface of the earth. As soon as
the mass of the body is separated from the earth,
gravitational attraction is set up between the two masses. The
earth pulls the man's body, and also his body pulls the earth,
but as the mass of the earth is infinitely greater, its
movement cannot be detected.

The scientists of today
believe that in some mysterious way the minute electrical
charges existing on the particles making up molecules and
atoms are definitely linked up and concerned with such basic
phenomena as gravitation. Since all bodies are made up of
atoms it would seem to logically follow that the forces of
gravity must depend in some way upon attractions which atoms
exert upon each other, and due to the fact that the atoms are
separated, at least in solids and liquids, by extremely small
distances, we might expect these inter-atomic forces to be
relatively more powerful than are those of ordinary
gravitation.

Until recently, however, the
mystery linking this inter-atomic activity with the force of
gravitation baffled all attempts at solution, although many
scientists had tackled it.

But at last experimental
proof has been forthcoming through the untiring labors of
Professor Francis E. Nipher, of the St. Louis Academy of
Science. In a pamphlet issued November 8, 1917, Prof. Nipher
supplies experimental evidence that gravitational attraction
can not only be suspended or nullified by the electrical
current, but it actually can be transformed into
"gravitational repulsion"!

All during the summer of
1917, Prof. Nipher had his apparatus in almost continuous
operation, and the experiments have been repeated time and
again, always with the same result.

Prof. Nipher's mechanical
apparatus resembled that used in the "Cavendish experiment",
by which it was first experimentally proved that Newton's law
of universal gravitational attraction applied to small bodies
in their action upon each other at short distances, just as
well as it did to small terrestrial bodies under the influence
of the earth. This apparatus consists of a delicate torsion
suspension fiber (**[Figure 3](#n1fig3)** &
**[Figure 4](#n1fig4)**), a light, rigid arm at
the lower end of the fiber suspension, and at either end of
this bar two small lead spheres of known mass. Two equal large
balls of solid lead are placed close to the small suspended
spheres in the manner shown. Now, remembering our law of
physics stated above -- that every body in space attracts
every other body proportionally to their respective masses and
inversely as the distance between them -- then it is evident
that when this apparatus is set up, that the small suspended
spheres will be slightly attracted by the larger, stationary
balls. This condition is represented in **[Figure
1](#n1fig1)**.

Before connecting any form
of electric current to the modified Cavendish apparatus, Prof.
Nipher took special precaution to carefully screen the moving
element from any electrostatic or electromagnetic effects. His
apparatus briefly consists of two large lead spheres ten
inches in diameter, resting upon heavy sheets of hard rubber.
Two small lead balls, each one inch in diameter, were now
suspended from two silk threads, stationed at the sides of the
two large lead spheres, from which they were separated by a
little distance. Moreover, the suspended balls were insulated
elaborately from the large spheres by enclosing them first
airtight in a long wooden box, which was also covered with
tinned iron sheets as well as cardboard sheets. There was,
furthermore, a metal shield between the box and the large
metal spheres. The large metal lead spheres now exerted a
certain gravitational pull upon the suspended small lead balls
as indicated in **[Figure 1](#n1fig1)**, and
the small lead balls were slightly pulled over towards the
large spheres.

In his first experiments
Prof. Nipher applied a high tension current from a static
machine to the large lead balls (**[Figure 2](#n1fig2)**).
No difference was noted whether the positive or negative
terminals were applied. In one of these experiments the masses
were "repelled" (normal gravitational attraction had been
nullified and changed to repulsion) by a force nearly twice as
great as the initial gravitational repulsion. The effect is
shown in **[Figure 3](#n1fig3)**.

In further experiments Prof.
Nipher decided to check his results. To do this he replaced
the large solid lead spheres with two metal boxes, each filled
with loose cotton batting. These hollow boxes (having
practically no mass) rested upon insulators. They were
separated from the protective screen by sheets of glass and
were grounded to it by heavy copper wires. The metal boxes
were then charged in every way that the solid lead spheres had
been, but not the slightest change in the position of the lead
balls could be detected. This would seem to prove conclusively
that the "repulsion" and "gravitational nullification" effects
that he had produced when the solid balls were electrically
charged were genuine and based undoubtedly on a true
inter-atomic electrical reaction, and not upon any form of
electrostatic or electromagnetic effects between the large and
small masses. If they had been, the metal boxes, with no mass,
would have served as well as the solid balls.

Another interesting
experiment was conducted with low frequency alternating
current applied to the large lead spheres. Spring contact
brushes were fastened to the wooden blocks supporting the
large spheres as shown in **[Figure 4](#n1fig4)**,
one brush on either side of the ball. This permitted sending
current through the ball from one side to the other. First, a
direct current of 20 amperes as sent through the two large
masses, but no effect on the suspended masses could be
detected. Next, an alternating current of 20 amperes was sent
through the two masses (See **[Figure 4](#n1fig4)**),
with
the
result that the gravitational attraction was quickly reduced
to zero, and not only that but in 15 to 20 minutes the small
lead spheres had moved over one-half as much to the opposite
direction as the distance they had been attracted originally
towards the large masses. Thus gravitation had not only been
completely nullified, but it was actually reversed.

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**Figure
1:
"Attractive"
effect of gravity between large & small masses. No
current.**

![](n1fig1.jpg)

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**Figure
2:
Gravitational
repulsion caused between large & small masses. Current
on.**

![](n1fig2.jpg)

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**Figure
3:
Nipher's
experiment with two metal boxes filled with cotton (no
mass). No gravitational change with or without current.**

![](n1fig3.jpg)

---

**Figure
4:
When
20 amps AC was passed through the large balls, the
gravitational attraction was reduced to zero and made
negative. This repulsion was 50% of the normal attraction.**

![](n1fig4.jpg)

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***Trans.
Acad. Sci. St. Louis,* pp. 163-175 (July 1916)**

**"Gravitation
&
Electrical
Action"**

by   
**Francis E. Nipher**

In former publications the
present writer has suggested an intimate relation between
gravitation and electrical action. (\*1)

(\*1: *Proc. Amer. Phil.
Soc. Philadelphia* 52: 283-6; *Science* (Sept. 1,
1911), pp. 282-3; *Experimental Studies in Electricity
& Magnetism*, pp. 19-24.

There can be no doubt of the
truth of the statement, that the attraction between any two
masses of matter, depends not only upon the amount of matter
in the two masses, and their distance from each other, but
also upon their electrical condition.

Assume that two spheres,
having radii R1 and r2, composed of
metal having a density *p*, and distant from each other
*r*, have electrical charges Q1 and Q2,
the spheres having a common potential *V*. their
attraction for each other will be:

(1)

![](n2form1.jpg)

Here *K* is the Newton
constant of gravitation as it would be determined if
electrical action were eliminated, or if *V* were zero
absolute.  The absolute zero in *V* would be the
common potential of the two bodies, under the condition
assumed in Eq. (1), when their attraction for each other is a
maximum.

The gravitation constant has
been determined by methods, which it was assumed made it
unnecessary to consider the electrical condition of the two
bodies. Nevertheless the results have been very
unsatisfactory. In his presidential address before the
American Mathematical Society in December 1899, R.S. Woodward
(\*2) referred to this constant as being one of the constants
of the solar system whose determination was in a most
unsatisfactory condition, as regards precision.

(\*2: *Bulletin Amer.
Math. Soc.* II 6: 153)

If the masses are capable of
acting upon each other electrically, and the final term in Eq.
(1) is omitted, that equation might be written:

(2)

![](n2form2.jpg)

In this equation an error of
*x* per cent in the value of *K* would result. By
(1) and (2):

![](n2form3.jpg)

If V is measured in volts:

(3)

![](n2form4.jpg)

For purposes of
illustration, assume that *K* = 6.6576 x 10-8
and that of R1 = 101, R2 = 1 and *p*
= 11.35; then:

*V* = 3.68 square root
of *x*

If the common potential of
the two spheres differs from absolute zero by 3.68 volts, the
value of K would be in error by one per cent of the above
value, which is that of Boys, unless adequate means are taken
to eliminate the effects represented by the final term of Eq.
(1)

If *V* were 8.23 volts
an error of 5% would result. If *V* were 36.8 volts, the
two spheres would have no attraction for each other, although
both would be attracted by the earth, even if it had the same
potential. The attraction of the earth for a gram of lead
would then be by (1):

A = 981 - 0.000,000,000,006.

The acceleration of a
falling body would be practically unchanged, and would not
depend upon the density of the matter of which it is composed,
as it would apparently be under the conditions assumed in Eq.
(1).

Rainbows falling through an
overcharged thundercloud (\*3) would repel each other. After
the diverging branches of a flash of lightning have penetrated
the cloud a new condition has arisen. Overcharged drops of
water along the lines of the intricate system of branches of
the discharge, have delivered their overcharge to the cloud at
the other end of the long flash. These drops are intimately
commingled with drops which are outside of the drainage lines.
The value of *V* for these two groups of drops now have
opposite signs. The final term in equation (1) then becomes
positive, as applied to these groups, and it is much greater
than the gravitation term. These drops coalesce as they fall
to earth and a brief dash of unusually large drops of rain
follows.

(\*3: The word overcharged,
or super-charged, was in common use more than a century ago,
when the one-fluid theory was in general favor.)

(\*4: See Nipher: "A Flash of
Lightning", *Popular Science Monthly*, Jan. 1912: p. 76;
Nipher: *Experimental Studies in Electricity &
Magnetism*, pp. 16-17))

In former papers above
referred to, an experimental study of explosive effects due to
a discharge from a large condenser through a small lead wire
was discussed. The wire was sealed within a glass tube filled
with coal oil. This work has been continued in a modified
form. Four quarter ampere wire fuses of lead were placed in
multiple across a gap, 5 cm in length in a line leading from
either terminal of an influence machine to a water-pipe
system. The other terminal was grounded on a gas pipe. The
lead wires were clamped between the leaves of two small brass
door hinges, one lead of each hinge being soldered to one of
the ends of the rods at the gap. Between the gap in which the
leaves were mounted and the ground was placed a large battery
jar filled with 4 liters of a solution of common salt. The
wire was parted at this point, and the ends were immersed in
this solution which thus formed part of the ground circuit.
One of the wires penetrated the liquid to a depth of about
half a cm. Between the gap in which the wires were mounted and
the machine was a spark gap, between knobs of equal radius.
The condenser consisted of 40 large sheets of glass (36 x 36")
having upon them 2 x 40 sq ft of tinfoil. The machine was
driven by a single-phase electric motor. Below the lead wires
a sheet of white paper was laid upon a plate of glass.

It was found that there was
a marked difference between the effect of the positive and the
negative discharge, or the compression wave, would cause the
lead wire to fuse and drop in hot globules upon the paper
below. The effect upon the paper is shown in Plate XLIV,
Figure 1. [Not available]

With the same adjustment,
the positive discharge3 causes the lead wires to rise in a
cloud of dust. If the paper were placed 3 cm below the wires,
it would usually be practically unaffected when the positive
discharge was used. In a few cases, as in Figure 2, it was
slightly discolored by the lead fumes.

Of course the discharge
could be made greater, so that either discharge would cause
the lead to be dissipated in a cloud. It could be made less,
so that fused metal would fall upon the paper when the
positive terminal was connected with the ground containing the
wire. In all cases the cloud effect was the more marked in the
case of the positive discharge, and the fused metal falling
upon the paper was less marked.

In case of the positive
discharge there is of course a heat effect. Part of the result
is due to this cause. But if we are to consider the positive
terminal as an exhaust terminal, into which the negative
electrons are suddenly drained and thence into the positive
sheets of the condenser, we may explain the result as an
explosive condition which is suddenly impressed upon the lead.
When deprived of negative corpuscles, each atom repels every
other. The negative term in question (1) has become very much
greater than positive, when applied to inter-atomic attraction
under these conditions.

The negative discharge,
which is to be regarded as a compression wave could not give a
super-charge to atoms within the wire, causing them to repel
each other. The super-charge is on the outside of the wire.
The one-fluid theory seems to furnish a more rational
explanation of these phenomena than the two-fluid theory, as
in the case in the phenomena of the Crookes tube.

Some work has been done in
the examination of the effect of the electrification of air
within a glass vessel, upon the pressure of the air on the
walls of the containing vessel. A large 3-necked Wolff's
bottle was used, the 3 openings being provided with rubber
stoppers which had been treated with vacuum wax. The bottle
had a volume of 9.6 liters. Through the central stopper was
passed a copper wire to which were attached 150 pins whose
heads were soldered to one of its faces. This many pointed
terminal could be placed directly in front of either of the
large knobs of the machine, at a distance of 10 cm, the other
knob, or terminal, being grounded.

A U-shaped water gauge was
mounted in another stopper of the flask. In the third stopper
of the flask a tube with a bulb containing calcium chloride
was mounted, this tube being provided with means for
connecting the confined air with the outer air. The condensers
were wholly removed from the machine. The glass bottle was
placed upon a sheet of heavy plate glass.

When the discharge-knobs of
the machine were near enough together so that the brush
discharge between them was accompanied by faint disruptive
effects, the pressure within the flask could be increased by
about 2 gr-wt per sq cm, the effect of the negative
electrification being somewhat greater than that of the
positive.  When the knobs were far enough apart to
prevent disruptive discharges, no luminous effects being
observed within the flask, the change in pressure due to
either terminal was reduced to 1 and 2 mm as shown by the
water gauge. After the pressure due to electrification of the
air had reached a final limit, a transfer of the may pointed
collector of the front of the other terminal, would result for
a time in a slow decrease in pressure, and then in a slow
increase to the former limit. The decrease in pressure did not
begin until the discharge from the other terminal had begun.
Heat effects had been practically eliminated.

If the gas contains moisture
a permanent decrease in pressure at once results, due to
condensation of vapor upon the sides of the vessel.

These results seem to
indicate that there is an electrical condition of the gas, for
which the Boyle-Gay-Lussac constant is at a minimum. When this
condition is reached, the second term of equation (1) is zero,
as applied to molecules of gas.

An attempt has been made to
determine whether or not the value of the gravitational term
of Eq. (1) can be affected by electrical action, when the
effect represented by the final term is eliminated. The
apparatus used was a modified form of that used by Cavendish.
The suspended masses consisted of 2 lead tubes, each being
about 15 cm length, each having a mass of 50 grams. They were
mounted around the ends of a bras tube 91 cm in length, and
having a mass of 30 gr. This tube was suspended upon 2 loosely
twisted threads of silk fibers, 180 cm length, whose distance
apart was approximately 0.4 cm, the twist was removed from
these threads by hanging upon each a mass of 65 grams. This
formed a very sensitive bifilar suspension. The suspended
masses were wholly surrounded by a metal shield of rectangular
form 10 x 12.5 cm in cross section. The suspension fibers were
enclosed in a metal tube, having a torsion head at the top,
thus providing means for properly adjusting the position of
the brass tube. The ends of the rectangular shield were
provided with metal caps, fitting closely into its ends. They
entered the shield a distance of 2.5 cm. An opening at the
middle of the shield, in front of a mirror mounted upon the
suspension wire, served for observation of position by means
of a telescope and scale. This opening was covered by a sheet
of glass which was sealed to the shield by means of sealing
wax. The window was covered with a metal wire screen having
about 5 wires per running cm. The mirror was observed through
this wire screen, the telescope being focused upon the scale
at the telescope. A change of one scale division represented a
change of 2.36 minutes of arc in the position of the suspended
tube. The suspended masses and the brass tube on which they
were mounted were surrounded by sheets of asbestos paper,
which fitted into the caps at the ends of the shield, and
fitted loosely the interior of the shield. These two linings
formed extensions of the end caps and were intended to prevent
a convection of the air within the shield.

The larger masses each
consisted of two 50-pound weights placed one upon the other
and mounted upon heavy columns of rubber. They were separated
from the metal shield by a space of about 2 cm. In this space
was placed a sheet of paper and 3 layers of asbestos paper.

The shield was mounted upon
a heavy piece of timber and rested directly upon a sheet of
glass. It was also wrapped with asbestos paper. The long
suspension tube was held in stable position by 3 heavy silk
cords attached to surrounding cases, and loaded with a series
of distributed masses varying from 50 to 100 grams each. The
metal shield was loaded with two 10-pound masses of iron and
its sides were clamped with wooden clamps in order to quiet
any vibrations in the shield. The large iron masses and the
metal shield were connected with each other by large copper
wires, leading to a spark-knob mounted upon a massive table.
The floor of the room was of reinforced concrete. The
discharge terminal was connected with the influence machine in
an adjoining room, by means of brass rods hung upon silk
cords. The machine was operated by a synchronous electric
motor. The discharge knobs at the machine were separated so
that no disruptive discharges were possible. One terminal of
the machine was grounded. There were no condensers on the
machine terminals.

The time interval of a to
and from vibration of the suspended masses was 485 seconds.
When at rest there appeared to be no disturbance of any kind.
The reading would sometimes remain constant for hours. At
other times the reading slowly changed. It often varied
throughout a day through 20 scale divisions. It was found that
the large masses appeared to attract the suspended masses with
a varying force, even when the former were hung from the
ceiling above. Sometimes they appeared to repel the suspended
masses. These varying effects were finally traced to very
moderate changes in the temperature of the room. It was found
that the flame of a wax candle, placed 14 inches from either
of the suspended masses, exerted a marked apparent attraction
for them. When a sheet of glass and two sheets of asbestos
paper were placed between the candle flame and the metal
shield, it being provided with a wrapping of asbestos paper in
addition to the inside lining of the same material, an
apparent attraction resulted. Fluctuations in the flame of the
candle due to the condition of the wick produced observable
effects. When the outer wall of the screen was rising in
temperature more rapidly on one side of the suspended mass
than on the opposite side, this mass moved towards the warmer
side. This was apparently due to the convection effect of air
within the lining of the metal screen.

The suspended rod bearing
the small masses was below the central axis of the enclosing
shield. If one side of the shield was warmer than the opposite
side the suspended rod would be in a slowly drifting current
of air, which would urge it towards the warmer side of the
screen, or away from the colder side. The temperature of the
large masses lagged behind that of the screen in the small
daily changed in the temperature of the room.

The effect of a noiseless
discharge from the pin-point terminal into the air around the
knob connected with the screen and the large masses, was to
produce an apparent decrease in the attraction of the large
masses for the suspended masses. This result was obtained when
no trace of disruptive discharge could be detected. After the
extreme displacement thus produced had been reached, the
distance between the pin-point terminal, and the knob
connected with the shield and the large masses, was increased
from 15 to about 90 cm, the charged bodies being then
grounded. This was done by means of a fine wire attached to an
insulated rod, which could be laid upon the floor of the room,
or lifted into contact with a rod, one end of which rested
upon one of the large masses. The pin-point terminal was
meantime made to face another grounded conductor. The
suspended masses then swayed to the other extreme position
during the next four minutes. By a repetition of this
operation, the arc of vibration could be increased from 1 or 2
scale divisions to 26 in the interval of an hour. The average
of the extreme readings of consecutive vibrations, usually
showed slow progressive changes of 2 to 5 scale divisions per
hour. Sometimes the average reading showed a decrease and
sometimes an increase. The results were of the same order of
magnitude whether the masses were connected with the negative
or with the positive terminal of the machine, although most of
this work has been done by the positive "discharge".

It was suspected that this
result might be due to a slight rise in the temperature of the
walls of the metal shield. If this were the case it must be
assumed that while the gap at the pin-point terminals was
least, the rise in temperature was least in that part of the
sides of the metal screen facing the large external masses.

In order to examine this
influence, a delicate air thermometer was extemporized. The
bulb consisted of an oil-can having a capacity of 4.5 liters
(1 gal). Connected by a rubber hose with the nozzle of the can
was a horizontal tube of glass, having a length of 75 cm and
an internal diameter of 0.76 mm. Within this tube was a short
column of water, serving as an index. The entire device was
insulated upon glass supports. A candle flame 20 inches
distant from the can was electrified and in electrified
contact with the large masses and shield, no change in the
position of the index column could be detected when observed
by means of a telescope.

The large masses were then
wholly enclosed in two metal boxes, from which the masses were
insulated. The masses rested upon rubber blocks placed upon
the bottom of the boxes, and each box was mounted upon rubber
blocks which rested upon plates of glass. The masses were in
the same position as in the work described above. The boxes
were separated from the shield, enclosing the suspended masses
by the plates of glass and the asbestos paper.

The two metal boxes and the
metal shield were then electrified precisely as has been done
before. It was then found impossible to increase the arc of
vibration of the suspended masses, although the operation was
continued for several hours. If the former results had been
due to heat effects, they should have produced the same
results in this case. The large masses were removed from the
enclosing boxes. The empty boxes and screen were then
electrified as before.

No change in the amplitude
of vibration could be produced.

These results seem to
indicate clearly that gravitational attraction between masses
of matter depends upon their electrical potential due to
electrical charges upon them. To assume a special case, such
as exists when the gravitation constant is being determined,
Newton's law holds only when the common potential of the two
bodies is such that their gravitational attraction for each
other is at a maximum. If the two masses are not separated by
a metal shield and their common potential is that of the
earth, these masses and their common potential is that of the
earth, these masses will repel each other by a force
represented by the final term in Eq. (1) and the value of *K*
will also be diminished, if the above conclusions are correct.
If the two masses are separated by a metal shield, this final
term will be eliminated, but the value of *K* will be
diminished and may seem to be variable, if there are local
variations in the potential of the earth. By adjusting the
potential of the attracting masses by well known means we may
hope that the real value of *K* and the absolute
potential of the earth may be determined. This is a problem
for the future to solve.

In the work discussed in
this paper an effort has been made to eliminate heat effects
from all sources. It may be that alternating discharges from a
high potential transformer would produce more marked effects
than have been observed by the methods above described. The
surging of negative electrons within the large attracting
masses would be greatly increased. This would also involve
heat disturbances, the effect of which would cast a doubt upon
the results. Under the conditions in which this work was done
the amplitude of vibration of the suspended masses sometimes
changed in a way that seemed to discredit the above
conclusions. It was finally found that variations in the
illumination of clouds in the northern sky produced marked
effects upon the position of the suspended masses. The
apparatus was fifteen feet distant from five large windows in
the north wall of the room. The variation in radiation from
such clouds was occasionally followed by a marked change in
the amplitude of consecutive vibrations. After such
disturbances and others not here referred to had been
eliminated, there still remained distinct evidence that the
value of the gravitation constant as it has been determined,
is dependent upon the electrical potential of the attracting
masses, when the effect represented by the final term in
equation (1) is wholly eliminated by a metal screen.

Plans are now being prepared
which will, it is hoped, result in a determination of the
change which can be produced in the value of the gravitation
constant, by electrification of the larger masses.

Figure 1: Fusion of lead
wire by negative discharge. [Not available]

Figure 2: Explosion effects
due to positive "discharge". [EV's ? Not available]

---

***Trans.
Acad. Sci. of St. Louis* XXIII (4): 177-193 (July 28,
1916)**

**Gravitational
Repulsion**

by   
**Francis
E. Nipher**

In a former paper published
by the Academy on July the following passage may be found:
(\*1)

(\*1: *Trans. Acad. of
Sci. of St. Louis*, XXIII (4): 173-176; July 28, 1916)

"These results seem to
indicate clearly that gravitational attraction between masses
of matter depends upon electrical potential due to electrical
charges upon them."

Every working day of the
following college year has been devoted to testing the
validity of the above statement. No results in conflict with
it have been obtained. Not only has gravitational attraction
been diminished by electrification of the attracting bodies
when direct electrical action has been wholly cut off by a
metal shield, but it has been made negative. It has been
converted into a repulsion. This result has been obtained many
times throughout the year. On one occasion during the latter
part of the year, this repulsion was made somewhat more than
twice as great as normal attraction.

The large masses used in
this work were spheres of lead ten inches in diameter. They
were mounted upon blocks of dry wood, which were mounted upon
caster-roller bearings. The wheels rested upon heavy sheets of
hard rubber. The suspended masses were two spheres of lead,
having a diameter of one inch, mounted upon the ends of a
brass tube. Their distance apart, from center to center, was
91.5 cm. They hung upon two untwisted threads of silk fibers,
forming a bifilar suspension. The length of the threads was
179 cm, and the distance between them was about 3.4 mm. Near
the top of the long metal cylinder enclosing these suspension
fibers, was a lateral brace formed of two bars of hard rubber,
about 30 cm in length. The ends of these bars formed a right
angle against which the vertical suspension cylinder was
pulled. These rubber bars formed the ends of two long bars of
wood attached to the tops of instrument cases along adjoining
sides of the room. The bars were also supported by a framed
structure. Silk cords attached to the cases ran along the two
bars and were tied to the suspension cylinder. Weights
distributed along these cords served to hold the cylinder
against the ends of the rubber bars. Vibrations of the
suspension cylinder were thus wholly eliminated. The torsion
head forming the top of the cylinder was provided with a rod
which extended radially outward to a distance of about 20 cm.
By this means the torsion head could be turned in order to put
the suspended masses into vibration. The top of the suspension
cylinder had a similar rod clamped to it having an upward
projecting stop, by means of which the torsion head could be
returned to the original position. Change in the temperature
of the air within the shield resulting in a change in volume
was provided for by the outflow or inflow around the torsion
head.

The enclosing case was of
the general form used by Cavendish. In the early part of the
year it was formed wholly of metal. It rested upon insulating
blocks of rubber, which were mounted upon two long pieces of
timber having a cross section of 4x4 inches. These timbers
rested upon a massive table, which was on a floor of
reinforced concrete within a building having granite walls. At
the central part of the metal shield the dimensions were 5x5
inches. A narrow slit on one side covered by a small plate of
glass sealed to the shield, served for observing the movement
of the suspended masses by means of a telescope and scale. At
the outer ends of the shield, the lateral dimension was about
15 inches. This form was chosen in order that the suspended
masses and the brass tube upon which they were mounted could
be inclosed by a cylinder of copper wire gauze, between which
and the outer screen was very loosely packed cotton fiber. A
thin layer of cotton was placed at the ends of the screen,
being also held in place by wire netting. This was designed to
diminish convection effects.

The body of the observer was
wholly below the level of the table. Radiation of heat from
the head to the screen was cut off by sheets of heavy
cardboard.

The two rooms used for this
work were wholly disconnected from the heating system of the
building. During the day the temperature of the large masses
was usually slightly lower than that of the shield around the
suspended masses. This temperature difference never exceeded
1.5 deg C.

The large masses were placed
at the ends of the screen or shield in line with the rod upon
which the small masses were mounted, in order to determine
their effect upon the time of vibration of this bifilar
pendulum. The large masses and screen were in direct metallic
connection, and the air around them was electrified by a
discharge from pin-points. A disc armed with 150 pins was
placed with the pin-points 4 cm. from each of the large
masses. A noiseless discharge was delivered from the points of
the pins.

Let *T* represent the
time of vibration when the masses were away.

Let *T*1
represent the time of vibration when the masses are in place.

Let *T*2 =
the time when the masses and screen are electrified. Then:

(1)

![](n3form1.jpg)

Here *m* is the
suspended mass, 2*d* the distance between the two silk
fibers on which it is suspended, and *l* their length. *I*
is the moment of inertia.

When the large masses are in
place:

(2)

![](n3form2.jpg)

Here *D* is the
directive constant of Eq. (1), *b* the distance between
the centers of the two suspended masses *m'*, and, and *r*
the distance between the suspended masses and the large masses
*M*. The equivalent of the brass rod is included in *m'*.

When the large masses are
electrified, if the time of vibration is increased to *T*2
and we assume that this is due to a decrease in the value of
the gravitation constant *G*, then:

(3)

![](n3form3.jpg)

From these equations:

(4)

![](n3form4.jpg)

The time of vibration was
determined by means of a chronograph belonging to the
department of astronomy of the University. The key was snapped
when the mean reading passed the cross-hair of the telescope.
The mean reading was obtained from the reading of the four
extremes of the two complete vibrations which immediately
preceded. The values here given are the mean of six complete
to and fro vibrations and the probable error does not in any
case exceed 0.25 sec.

Observations March 10, 1916:

*T* = 623.0 sec.
  
*T*1 = 614.5
sec.   
*T*2 = 625.0
sec.

By Eq. 4, *n*/100 =
1.23

When *T* was
determined the temperature of the air the room was 15.5 deg C = ta.

The temperature of the
screen was t8= 15.2 deg C.

When *T*1
was determined,

*t*a = 17.4 deg
C   
*t*8 = 17.4 deg
C

The temperature of the two
large masses was 16 deg and 16.6 deg.

These values were determined
by means of four thermometers reading to tenths of a degree.
The bulbs were placed in contact with the masses, and covered
with a layer of cotton batting.

When the readings for *T*2
were finished,

*T*a = 18.0 deg
C   
*T*8 = 17.9 deg
C

The temperature of the large
masses was 17.7 degand 17.8 deg.

On a former occasion, when
the bifilar suspension different, it was found that placing
metal vessels containing a liter of water having a temperature
of 28 deg C. at the beginning of the experiment, and 24 deg at the
close, in positions occupied by the large masses, the
temperature of the air and shield being 13 deg,8, the value of *T*
was increased  from 644.2 sec. to 652.5. The warm vessels
were in contact with the shield.

When the metal vessels
contained water and ice, temperature of the air and shield
being 12.0 deg, the value of *T* was decreased by 25
seconds.

These results seem to
indicate clearly that convection of the air within the shield
had no material effect upon the values of the quantities used
in computing the value of *n* in Eq. 4.

It apparently follows that
the value of the gravitational constant was made negative by
the process described. Attraction was converted into a
repulsion. The influence machine was unusually active by
reason of fresh dry material in the case in which it was
enclosed. On other days the value of *G* was decreased
by 16, 23, 27, 69, 77, 134 and 184 per cent of its initial
value. It is not claimed that these are results of any high
degree of precision. During the first week while the bifiar
method above described was being tested, the time of vibration
during a period of two hours was found to be very constant.
For example, in the first determination made on October 23,
the mean position of the suspended masses was determined from
readings of the extremes for several vibrations. The key was
then snapped for six readings while the mean reading passed
the cross-hair of the telescope. The mean reading was
determined in each case by a computation from previous
readings. It was found to be very constant. After lunch the
same operation was repeated. This gave six readings of the
time interval of 7 complete to and fro vibrations, with data
for determining the probable error of the mean. The result was
653.45 +- 0.062 seconds. The probable error was sometimes
three times as great as the above value and the mean value
varied from the above value on other days by between one and
two seconds. An error in the value of n might amount to three
or four per cent. The cause for the variations proved to be a
difficult problem. The silk threads were very loosely wound,
and before they were put in place a weight equal to half the
weight of the entire suspended mass was hung upon each of them
for several days. They then seemed to be in permanent
condition. The breaking stress was about five times that which
was thus applied to them.

The causes for the variation
in the time of vibration were thought to be possibly due to a
breaking of some of the fibers in the threads which might
result in an entanglement between the two threads, or which
might result in an unequal division of the load between them.
It  was sought to eliminate the former source of error by
applying vaseline to the threads. This did not appreciably
change the result. It was finally decided to check the results
above described by placing the large masses on alternate sides
of the suspended masses and observing the deflection doe to
gravitational attraction.

In order to maintain
equality of stresses in the two threads, which had been hung
around a hook attached to the torsion head, they were hung
around a pulley, having a diameter of one inch. Below were two
adjustable pulleys. The threads approached each other around
these two pulleys, and their distance apart could be so varied
as to make the threads parallel within the suspension
cylinder. The metal shield before described was replaced by
one having equal width from end to end. The top, bottom and
ends were of wood 1/8 inch in thickness. A sketch of this wood
frame is shown in vertical section in **[Figure
1](#n3fig1)**.

---

  
**Figure
1 ~**
![](n3fig1.jpg)

---

This wood frame was
varnished with shellac and the points of contact of its parts
were closed. The sides this frame were each closed by two
layers of heavy cardboard outside of which was a sheet of
flexible tinned iron. They were clamped to the wooden frame by
means of wood bars screwed to the bottom, top and ends. The
edges of the cardboard were then scaled by means of beeswax
applied by means of a hot iron. The entire device as thus
described was then enclosed by a metal shield. A cross section
through one of the suspended masses is shown in **[Figure 2](#n3fig2)**.

---

  
**Figure
2 ~**
![](n3fig2.jpg)


---

This outside metal shield
was not air-tight. It was formed of sheets of flexible tinned
iron, the parts of which overlapped. They were tied in place
by windings of twine. It was considered an advantage to allow
convection currents which might form in the layer of air
between the two sheets of metal forming the sides of the
enclosing case some opportunity to escape into the outer air.

The large masses *M*
were thus separated from the suspended masses *m'* by
two superposed sheets of cardboard and a sheet of metal, which
were clamped and sealed to the wood frame of **[Figure 1](#n3fig1)**, a layer of air about 0/8
inch thickness, and the outer sheets of metal, forming part of
the metal shield enclosing the entire device.

Both of the masses *M*,
and the shield around the suspended masses, were insulated as
before described. The large masses and the shield around the
suspended masses were connected by means of large copper
wires. Between the masses *M*, and the shield were
sheets of glass, not shown in **[Figure 2](#n3fig2)**.

In the work to be described,
the air around the large masses and screen was electrified by
a noiseless discharge from 800 pin points which were mounted
in strips of metal hung upon insulated metal rods three feet
from the large masses and screen. A sketch of this arrangement
as shown in **[Figure 3](#n3fig3)**. The sheets
of metal which carried these pins were punched with small
holes, through which the pins were inserted and the heads were
then soldered to the sheets of metal, which were then hung
upon the insulated rods by metal hooks. At one end this line
of rods terminated in a disc of metal upon which 150 pins were
mounted. Facing this disc was a duplicate, the points of the
pins in the two discs being three or four inches apart. This
last named disc was directly connected with one terminal of an
influence machine in an adjoining room, the other terminal
being grounded on a water pipe. There were no condensers
attached to the machine, and the knobs were widely separated.
There were no gaps in the line of conductors. The machine was
enclosed in a glass case containing drying material, and it
was driven by a single-phase motor. Placing the large masses
in the position shown in **[Figure 3](#n3fig3)**
at the time when the work to be described began, increased the
scale reading by 0.40 cm.

---

  
**Figure
3 ~**


![](n3fig3.jpg)

---

An illustration of the
results obtained is shown **[Plate XLV](#n3plate)**.
In each case the masses had been grounded during the preceding
night. The scale was displaced in order that the two diagrams
might be shown on the same plate, without interference. On the
lower diagram the arrangement of apparatus was as shown in
Figure 3. The hour of the day is laid off upon the horizontal
axis. The scale reading in cm. is along the vertical axis. One
mm represents an angle of 2.6 minutes of arc. The negative
terminal was applied at 9:38 a.m. On the diagram the arrow
indicates the time. At 10:12 a.m. the terminals were reversed,
an operation which required a few seconds of time. At 11:30
the machine was disconnected. There was evidence shown in the
drop in the reading at 11:20 that the reading would begin to
decrease. The upper diagram of this plate shows results
obtained on May 4. Here the positive terminal was first
applied at 9:35  a.m. The terminals were reversed at
10:24 and the machine was stopped at 11 :20, the readings
being continued to 12:05 p.m. In this work the conductors upon
which the 800 pins were supported were directly connected with
the large masses and shield.

When direct contact was made
between the pin-conductors and the large masses, the changes
took place more rapidly than when the air surrounding the
masses was supercharged with negative corpuscles emitted from
the pin points, or when the reverse action took place, this
alone being depended upon to change the potential of the
masses. The most interesting feature of this work is the
complete elimination of the possibility that the apparent
decrease in the attraction between these masses was due to the
convection currents of air resulting from heat effects.
Reversing the terminals would not reverse the heat effects.

The possibility that one
terminal of the machine produced greater heat effects than the
other, the deflecting effect being decreased when the terminal
producing the lesser heating effect was applied is also
eliminated. It matters not which terminal is first applied.
The result is the same, and has been obtained many times.

During the afternoon of May
4 the operation represented in the upper curve of Plate XLV
was repeated, the positive terminal being first applied. A
result of precisely the same kind was obtained.

The upper curve of **[Plate XLV](#n3plate)** also means that the
gravitational attraction between the masses at 9:35 a.m. had
been decreased by about 110% at 10:10 a.m. Gravitational
attraction had been decreased to zero, and had then been
converted into a repulsion. An hour later it had regained its
initial value. On the afternoon of June 1, 2:30 p.m., it was
decided to change the electrical condition of the suspended
masses. One of the end caps forming the outer metal shield of
Figure 2 was removed. A hole which had been bored through the
wood frame, and which had been closed by a rubber stopper, was
opened. A glass tube was passed through the opening, about two
centimeters beyond the inner surface of the wood frame. A
copper wire to the end of which the head of a pin had been
soldered, was passed through the tube, the point of the pin
projecting slightly beyond the end of the tube.

The wire was about six
inches in length. The apparatus was arranged as shown in **[Figure 3](#n3fig3)**. The positive terminal of
the machine was used in draining negative corpuscles from the
air within the shield around the suspended masses. A slow
change of 1.2 cm. or 12 scale divisions in the scale reading
was produced. The terminal was disconnected when this
deflection had been produced and the machine was stopped. The
tube was removed, the end cap of metal was replaced and the
large masses and shield and the pin-point conductors were
grounded until the next day. The mean rending had not been
appreciably changed.

At 10:25 a.m., June 2,
readings were taken until 10:43 a.m. The suspended masses were
at rest. The positive terminal was then applied. The result is
shown in Plate XLVI. The arrangement of the apparatus was that
shown in **[Figure 3](#n3fig3)**. A sudden
decrease in the attraction occurred. It was so sudden that
forced vibrations were impressed upon the suspended masses.
The vibrations were small, and only occasional readings of
consecutive extremes were recorded. At 2:20 p.m. the terminals
were reversed and at 2:32 p.m. direct contact of the pin-point
conductors and the large masses and shield was made.

The attraction at once
increased very rapidly. The absolute zero of potential was
reached and passed in a less time than that of a
semi-vibration. Forced vibrations were impressed upon the
suspended masses as the attraction began to decrease. These
vibrations were observed, and the extremes were read until
3:30 p.m. The masses were then being repelled by a force
nearly twice as great as the initial gravitational attraction.
Direct contact between the discharge points was removed, but
the masses were not grounded. On Monday, June 4, at 9:20 a.m.,
the masses were vibrating over a very small arc (about one
scale division). Readings were taken at some of the extremes
of vibration, which were sufficient in number to show that the
mean reading was constant until 11 a.m. These readings are
represented in Plate XLVII. The masses were still repelling
each other, with a force about 50 per cent greater than the
initial attraction on the morning of June 2. This conclusion
seemed beyond belief at the time but subsequent results on
that day seemed to make it a necessary conclusion. At 11:03
a.m. the positive terminal was applied and direct contact
between the large masses and the pin-point conductors of **[Figure 3](#n3fig3)** was made. The time is
represented by the arrow marked +DC on Plate XLVII.

At once the attraction began
to increase. The masses were swaying in the opposite direction
at the time when contact was made. A maximum reading was
obtained at 11:18 a.m. and the masses swayed in the opposite
direction during the next 14 minutes. Forced vibrations were
again impressed upon the suspended masses, but they were less
violent in character than those at the close of the
observations; represented in Plate XLVI. At 12 observations
were discontinued until 12:48 p.m., when the reading showed
only a slight decrease. At 1:00 p.m. the terminals were
reversed and the direct contact was removed. The conditions
then were as represented in **[Figure 3](#n3fig3)**.
At this time the apparent decrease in the initial attraction
which existed at the beginning of the observations on June 2,
was about 340 per cent. In other words the apparent repulsion
was then more than twice the initial attraction. This
conclusion seems to be fully justified by the amazing increase
in the attraction which at once resulted. At 1:53 p.m. direct
contact between the pin-point conductors and the shield and
large masses was made by dropping a wire into position. It was
removed at 2:02 p.m. Forced vibrations were again impressed
upon the suspended masses. The machine was stopped at 2:19
p.m. and I was called away for an bour. A few readings taken
between 3:12 and 3:22 p.m. shown at the close of Plate XLVII
indicate that the attraction had then approached closely to
the initial value on the morning of June 2.

It will of course be
understood that no attempt has been made to secure results of
precision in this work. The only aim has been to determine
whether or not it would be justifiable to construct the much
more expensive apparatus which will be required for such
results. The suspended masses must be capable of being
electrified independently and the enclosing walls must
surround them in symmetrical form, so that their inductive
action will not produce deflection of the surrounded masses.
If they are suspended in highly rarefied air, it may be
necessary to use a metal wire rather than a quartz fiber,
which must then be attached to an insulated torsion beam. A
modified form of the apparatus used by Boys will be required.
The necessity for such a construction seems to be justified by
the evidence already obtained, that if the potential of either
of the attracting masses M and m' is zero absolute,
gravitational attraction between them will not be affected by
varying the potential of the other mass. The gravitation,
constant as it has been determined by methods which made use
of some form of the Mitchell-Cavendish apparatus, would have a
maximum value when either or both of the masses had a
potential of zero absolute.

Neglecting the inductive
effect which electrified masses have upon each other, it is
possible that the amended equation for gravitational
attraction between them is:

![](n3form5.jpg)

It seems possible that the
effect of the charges Q and Q' upon gravitational attraction
between the masses m and m' may be a surface effect. If so the
values of Q and Q' may be replaced by RV and R'V', where R and
R' are the radii of the two masses and V and V' their
potentials due to those charges.

The above equation may also
be written:

![](n3form6.jpg)

Here it is assumed that the
masses are so electrified as to diminish their normal
attraction for each other by n per cent. From these two
equations the values of m and m' being replaced by their
values in terms of volume and density.

![](n3form7.jpg)

If this equation really
represents the conditions imposed upon the masses, it appears
that for any given decrease in gravitational attraction the
potentials of the masses must be directly proportional to the
surface areas of the masses. Small planets having high and
perhaps varying potentials might not follow Newton's law. The
value of *n* would be large and variable.

In the work represented in
Plate XLVI, if we assume that when n was l00, the attraction
between the masses being reduced to zero, the potential of the
large masses was 30,000 volts, or 100 E.S.C.G.S. units, and
that of the suspended masses was 10 volts or 1/30 E.S.C.G.S.
unit, then the last equation would give for *K*':

*K*' = 165800 *K*

This result is based upon
assumptions and estimates. One inference may be drawn from it.
There is nothing here to indicate that the force whose action
is represented by Newton's term, should not be the main factor
in determining the motion of the masses in our planetary
system.

The large masses represented
in **[Figure 1](#n3fig1)** were replaced by
boxes of metal, filled with loose cotton batting. They rested
upon insulators. They were separated from the screen by sheets
of glass, and were put in metallic contact ,vith it by means
of copper wires. Precisely the same treatment was applied to
this system as was given when the large masses were in place.
No change in the position of the suspended masses could be
detected.

The large masses being in
position as before described, spring contact brushes were
fastened to the blocks of wood upon which the large masses
rested. They made contact with the large masses at points
midway between the top and bottom of the spheres. A direct
current of 20 amperes was sent through the two large masses.
The axis of the line of flow was in one case practically
coincident with the line through the centers of gravity of the
two masses nearest to each other. The direction of flow was
either from the outside contact, to the one nearest the
screen, or the reverse, the direction of flow being reversible
by means of a double switch. The screen was insulated from the
two large spheres. No effect upon the suspended masses could
be detected. If any effect was produced it was very small. The
large masses were turned 90 deg in position, with a like result.

An alternating current of 20
amperes was applied. No effect could be detected when the
masses were in the latter position. When the lines through the
points of contact with the brushes with the large spheres was
coincident practically with the line through the centers of
gravity of the two masses nearest to each other, the
gravitational attraction was quickly reduced to zero, and made
negative. When the double switch was opened, so that the large
masses were wholly separated from the source, and the masses
were grounded it required between two and three hours for the
large masses to recover from the shock which they had
received. This has been repeated many times, with no
discordant results. It may be that the parts of the large
spheres which are most affected by the alternating current are
those parts near the brushes. If there are heat effects, they
tend to oppose the observed effect. Burning candles replacing
the large masses cause a change in reading in the opposite
direction from that of the alternating current, the glass
plates being removed. This is due to convection currents
within the screen.

The work here described has
been done in a private laboratory in the second story of Eads
Hall, now occupied by the physics department of Washington
University.

My thanks are due to the
Carnegie Institution of Washington for meeting the expense of
this work.

---

**Plate
XLV:
Variation
in Gravitational Attraction**

![](n3fig4.jpg)

---

Plate XLVI: Variation in
Gravitational Attraction [Not available]

Plate XLVII: Variation in
Gravitational Attraction [Not available]

---

***Trans.
Acad. Sci. of St. Louis* XXVII: 383-387 (March 2, 1920)**

**New
Evidence of a Relation Between Gravitation &
Eelctrical Action, & of Local Changes in the
Electrical Potential of the Earth.**

by   
**Francis E. Nipher**

In the work to be here
described, the apparatus used was a modified form of that used
by Cavendish, as shown in the former paper, published by the
Academy of Science of St. Louis, Vol. XXIII, pp. 183-185.

The wood frame was in this
case covered with tin-foil, within and without. The sheet
metal forming the sides of the shield were clamped to the wood
frame, by bars of wood which were also covered with tin-foil.
All joints were sealed with wax before the tin-foil was put in
place.

The whole shield was then
surrounded by two end caps of metal which meet at the middle
or the shield and are scaled together by means of tin-foil. A
layer of air was thus formed between the two metal shields
surrounding the suspended masses. Either of these two metal
shields was considered ample protection to prevent the
suspended masses from being acted upon electrically by the
large masses. The layer of air between the two shields was
designed to diminish convection effects within the shield due
to changes in the temperature of the room, and changes in the
temperature of the air within the room were made as small as
possible by cutting off all sources of artificial heat. It did
not usually vary more than 1.5 degrees C. during the day. The
temperature was determined by means of a thermometer placed
near the large masses. The reading was by means of a
telescope. The reading could be made accurately to tenths of a
degree C and hundredths of a degree could be estimated with
fair precision. The air within the shield was electrically
charged by means of a wire armed with a pin which was thrust
through the end of the shield about an inch above the level of
the suspended masses, and was sealed in place. The inner end
of the tube was drawn to a small diameter, being only large
enough to admit the end of the pin. This could be withdrawn at
any time and the outer end of the tube could be covered with a
metal tube which was closed with a metal plug at its outer
end.

Convection effects, due to
changes in temperature, have been very carefully studied. When
the masses have not been electrically charged for several
days, the rise in the temperature of the room during the day
caused a very slow increase in the scale reading which
determined the position of the suspended masses. This change
in position decreases the distance between the suspended
masses and the large masses. When a door opening into the
hallway was opened for four minutes this change is larger and
more abrupt. When an outside window was opened, admitting cold
air, a sudden decrease in the reading results.

The room containing the
apparatus was always entered from an adjoining room, from
which heat from the heating system was wholly cut off.

In order to decrease
convection effects, the large masses and shield were covered
on all sides with a pile of cotton batting, forming a layer of
about 6 to 8 inches thickness. This was permissible by reason
of the fact that the electric machine in the adjoining room
was discarded as a source of electricity. It was replaced by
the earth, which had been found to be equally effective, and
which has a much greater capacity. The large masses and
shield, and when necessary, the injection pin were connected
by wire with a copper lightning rod on the outside of the
building. This rod formed the ground connection for a steel
tower used for wireless. Its top was 100 feet above the
ground. This tower is mounted upon the roof of the physics
building, the walls of which are red granite. The room
containing the apparatus is on the second floor of this
building, and below the tower.

Twelve copper wires about
ten feet in length were soldered to the lower part of the
lightning rod, and spread over the ground, their ends being
injected a few inches into the soil. The wire leading from the
masses within the building to the rod was also soldered to it.
Connected with this wire within the room containing the
gravitating masses were metal rods surrounding the apparatus
which were hung sheets of metal to which were attached about
one thousand pins. Small holes were punched through the metal,
the pins were inserted, and the heads were soldered to the
metal, This was intended as a means to put all of the air in
the room in an electrical condition as near uniform as
possible.

With such an apparatus a
determination of the gravitation constant would be utterly
impossible, the position of the suspended masses changes from
day to day and from night to day by greater amounts than was
at any time possible when the plate glass machine was used for
the electrification of the masses. Their position depends upon
the weather and upon the moisture in the surface of the earth.
The changes were often greater than was ever caused by the
removal or replacing of the large masses. Results obtained on
December 12 last are alone sufficient to establish the fact
that enormous local changes in the earth's potential are
constantly occurring, and that these changes produce
variations in gravitational attraction between the large
masses and the suspended masses.

On December 5 and 6 over an
inch of rain and sleet fell, and on December 8 and 9 there was
a light fall of sleet. The minimum temperature gradually fell
from 28 deg on the 5th to 1 deg on the 10th. The ground was covered
with a thin layer of ice and snow on the 12th. On that day the
morning temperature was 20 deg but rose to 56 deg. The ground around
the lightning rod between the building and a walk about 12
feet from the building was very dry, having been shielded by
the building. During the forenoon the large masses and the
injection pin for electrification of the air within the shield
were connected with the lightning rod. Between 8:50 a.m. and
11:45 p.m. the scale reading decreased very slightly but with
no vibrations. The temperature of the air around the shield
increased by 1.5 deg C. The injection pin was then withdrawn and
the glass tube was covered with the metal cap. Vibrations of
the suspended masses at once began. The scale reading varied
through about three divisions of the scale. This amplitude had
diminished to about two divisions of the scale at 1:20 p.m.
The time of a complete vibration was about 9 minutes. The
frozen ground outside of the walk was then covered with a thin
layer of water. Eight buckets of water were splashed over the
ground around the lightning rod, covering the area over which
the copper wires were spread, this wet area thus formed being
finally connected with the wet ground beyond the walk. The
scale reading abruptly diminished during the next three
vibrations. The change in the average reading was about 80% of
the change formerly produced by the removal of the large
masses to a position of no deviation in the position of the
suspended masses.

This determination of the
deviation, due to the large masses, was obtained before
electrification of the mass was begun. They were, however,
then above the surface of the earth, and subject to the
inductive action of the atmosphere.

The results described in
this paper indicate that the disturbances here discussed would
be greatest if the work were done on a barren island, in a
building above the level of the surrounding water. It is under
such conditions that the phenomenon known as St. Elmo's fire
is commonly observed. On land each blade of grass and the
leaves of trees have a function similar to that of the masts
of ships provided with lightning protection. They are
individually less effective, but they are far more numerous.

In order to eliminate these
disturbing effects the work should be done in a room below the
surface of the earth the walls, ceiling and floor being of
metal. Insulate copper wires within copper tubes should be
connected with the masses. Those connected with the suspended
masses should terminate in a cup of mercury. A flexible chain
of metal attached to the middle of the bar carrying the
suspended masses, should be provided at its lower end with a
fine platinum wire, making contact with the mercury surface.
These protected copper wires should be grounded in a well of
water. The water in this well must be protected from any
inductive action of the atmosphere.

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