Hi all,
A brief update.
A number of people have emailed me re the nexus article.
Some are amazed and some want more infromation.
Can I ask all interested physics guys here to post what they want expanding.
Some question the centrifugal effect and I refer them to Tolman?s work of 1915, I provide an extract below.
Some are a bit confused about energy in though I believe it is explained in the article in the science news section of the website.
Anyhow, if you can post what you want or would like to see I will gey busy.
Regards Phil
PS please be patient with the site as each page can take a few seconds to load.
I have asked the web guy to get rid of flash but he has not got round to it yet.
Some wanted better drawings and I will also attend to that in the next few days.
Also the site is being checked out by Steorn forum but when I tried to sign up it rejected my application. Does anyone know about Steorn forum? They have been checking out the website heaps of times.
Cheers
Tolman extract
FURTHER EXPERIMENTS ON THE MASS OF THE ELECTRIC
CARRIER IN METALS
By RICHARD C. TOLMAN, SEBASTIAN KARRER, AND ERNEST W. GUERNSEY
FIxZD NITROGEN RZSZARCH LABORArORY, WASHINGTON, D. C.
Communicated, March 21, 1923
Introduction.-The production of an electromotive force by the accelera-
tion of a metallic conductor was apparently demonstrated by the work of
Tolman and Stewart [Physic. Rev., 8, 97 (1916); 9, 164 (1917) ], by measur-
ing the pulse of electric current produced by suddenly stopping a coil of
wire rotating around its axis. The purpose of the work described in the
present article has been twofold. In the first place it seemed desirable
to obtain a new demonstration of this production of an electromotive
force by the acceleration of a metal, using some method of attack as dif-
ferent as possible from that of Tolman and Stewart, in order to increase
our certainty as to the reality of the effect. In the second place it seemed
desirable to try to find a method which would eliminate direct electrical
connections between moving and stationary parts, and would avoid the
sudden stopping of a coil of wire, 'with the attendant chance of irregular
electromotive forces due to buckling or slipping of the wire.
Apparatus.-The apparatus finally used consisted of a copper cylinder
91/8 inches long, 4 inches outside diameter, and 3 inches inside diameter,
oscillating about its axis with a frequency of 18.9 cycles per second.
Surrounding this copper cylinder was a coil containing about 60 miles of
No. 38 copper wire (diam. 0.1 mm.), which acted as the secondary of
a
transformer. Connection from this secondary was made through a spe-
cially designed three stage amplifier with a vibration galvanometer. The
tendency of the electrons in the oscillating copper cylinder to lag behind
because of their inertia leads to an electromotive force, the effects of which
were finally measured by the deflection of the vibration galvanometer.
These galvanometer deflections were then compared with those produced
VOL.9,1923 PHYSICS:TOLMAN,KARRERANDGUERNSEY 167
by the known electromotive force accompanying transverse oscillation of
the cylinder in such a way as to cut the earth's magnetic field.
The apparatus was mounted on a massive concrete pier in a special
location 150 yards from the nearest electrical circuits, was con-
structed without the use of magnetic materials, and was driven by air
pressure to avoid the disturbances which would have been produced
by electrical driving. The axis of the oscillating cylinder was made
parallel to the earth's magnetic field in order to reduce accidental
effects.
Theory of the Experiment.-The experiments consisted in comparing
the electromotive force produced in the cylinder by its rotary oscillation
with the electromotive force produced by its transverse oscillation in
such a way as to cut the earth's magnetic field. The elementary theory
of the experiment may be developed as follows.
If a longitudinal acceleration a is applied to a metallic conductor, the
electrons within the conductor will tend to move relative to the main
body of the metal as though the conductor were stationary and the elec-
trons were acted on by the force.
f = ma (1)
wheremmaybecalledthe"effectivemass"oftheelectron. Ontheother
hand if an electromotive force E is applied to a stationary metallic con-
ductor of length I and uniform cross-section, the electrons within the
conductor will be acted on by the force
f = Ee/l (2)
where e is the charge of one electron. Since the "fictitious" force given
by equation (1) and the "real" force given by equation (2) both tend to
make the electrons move relative to the main body of the metal, it is evi-
dentthattheymaybeequated inordertogetanexpressionforthe electro-
motive force produced by the longitudinal acceleration of a metallic
conductor. We obtain, for the electromotive force E, produced in a metal-
lic conductor of length 1, by an acceleration a the expression
E = mla/e (3)
Let us now consider the rotary oscillations of the cylinder around
its axis. At any radius r we may evidently write for the instantaneous
acceleration, the expression
a-47r2v20er sin 27rvt (4)
18PHYSICS:TOLMAN,KARRERAN)DGUERNSEYPROc.N.A. S.
where v is the frequency of harmonic oscillation and 0 is half -the angular
amplitudeofoscillation. Substitutinginequation(3)andtakingthelength
of the conductor at the radius in question as 2rr, we obtain
Fe = 8Xr3V2r2(m!e)Oe sin 2irvt (5)
as an expression for the electromotive force around a current sheet located
in the cylinder at the radius r.
Let us now compare this electromotive force with the electromotive
force produced by the transverse oscillation of the cylinder in the earth's
fieldusedincalibrating. IfQcisthe.halfangularamplitudeoftransverse
oscillation, we may write for the maximum flux through a current sheet
of radius r, the expression
9b max = iri>2H sin OC = 7rr2H6, (for small amplitudes) (6)
where H is total intensity of the earth's field. Hence for harmonic os-
cillation of frequency v, we may write for the electromotive force pro-
-
duced in carrying out the calibration the expression
c= 2ir2vr2HGc sin 27r't. (7)
Dividing equation (5) by (7) we obtain for the ratio of the electromotive
forces produced by the effect and in calibration the expression
E;eEc = (4wv/H),. (mle) . (Oe/IO) -(

or soiving for the thing of interest, namely the ratio of the effective mass
of the electron to its charge,. we obtain,
m/e = (H/47rv) . (EJEC) * (O,/O0e) (9)
This is the equation which was used in calculating our experimental re-
sults. It will be noted that the radius r of the particular current sheet
has dropped out so that Ee/EC may be taken as the ratio of the total elec-
tromotive forces produced by the rotary oscillation and transverse os-
cillation of the effect cylinder.
In carrying out the actual experiments, a comparison was made of the-
galvanometer deflections produced by the rotary oscillation of the main
cylinder and the transverse oscillation of a much thinner walled calibra-
tion cylinder, which was driven with the same frequency as the main.
cylinder and surrounded by a similar secondary coil. This made it
possible to eliminate variability in the behavior of the amplifier by ob-
VOL.9,1923 PHYSICS:TOLMAN,KARRERANDGUERNSEY
taining nearly simultaneous readings from the main cylinder and the
calibration cylinder. At the close of the experiments a "master calibra-
tion" was made comparing the electromotive forces produced by the trans-
verse oscillation in the earth's field of the main cylinder and the calibra-
tion cylinders which had been employed. We could than calculate the
ratio Ec/Ec which occurs in equation (9) by putting it equal to the ratio
of the galvanometer deflections obtained from the main cylinder and from
the calibration cylinder multiplied by the ratio determined in the master
calibration. The other quantities in equation (9) were determined by
direct measurement.
Experimental Results.-In all-, eighty-six measurements were made.
The average value of m/e in grams per abcoulomb was 5.18 X 10-8,
with an average deviation of 1.33 X 10-8. The average deviation divided
by the square-root of the nu,mber of observations was 0.14 X 10-8.
Conclusion.-It is felt that the work presented above may be regarded
as another fairly satisfactory demonstration of the production of elec-
tromotive forces by the acceleration of a metallic conductor, and as indi-
cating again that the mass of the carrier in metals is about the same as
the mass of an electron in free space. The new work taken by itself alone
is perhaps not as convincing as the work of Tolman and Stewart, because
of the greater complexity of the apparatus, because of the fact that time
did not permit a satisfactory neutralization of the earth's field, and be-
cause further developments of the method would be necessary in order to
show that the direction of the effect is that predicted on the basis of
a
mobile negative carrier. Our total certainty as to the reality of the effect
is, however, greatly increased by the fact that two such widely divergent
methods have led to concordant results.
Values of mle obtained in different ways are given below, in grams per
abcoulomb.
m/e in free space 5.66 X 10-8 (cathode rays)
m/e in copper 6.24 X 10-8 (Tolman and Stewart)
m/e in silver 6.73 X 10-8 (Tolman and Stebvart)
m/e in aluminum 6.50 X 10-8 (Tolman and Stewart)
m/e in copper 5.18 X 10-8 (Tolman, Karrer and Guernsey)
It is evident that.our data are not yet accurate enough to determine
whether the mass of the electron in a metal is precisely the same as that
in free space or not.
A more complete account of the experimental work containing a dis-
cussion of the sources of error in the work will be published in the Physical
Review. The investigation is being continued at the California Institute
ofTechnology.