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EltronBKP/ElectronC
This website contains an archive of files for the Acorn Electron, BBC Micro, Acorn Archimedes, Commodore 16 and Commodore 64 computers, which Dominic Ford has rescued from his private collection of floppy disks and cassettes.
Some of these files were originally commercial releases in the 1980s and 1990s, but they are now widely available online. I assume that copyright over them is no longer being asserted. If you own the copyright and would like files to be removed, please contact me.
| Tape/disk: | Home » Personal collection » Acorn ADFS disks » Electron » Pixel_map.ADF |
| Filename: | EltronBKP/ElectronC |
| Read OK: | ✔ |
| File size: | 1D6E bytes |
| Load address: | D0D6576 |
| Exec address: | 1010100 |
File contents
�.........*.......*.......*.......*.......*.......*.......*.......*.......*.<
This still left the difficulty that Hertz had failed to deflect the
cathode rays by applying an electric field. Thomson was suspicious about
this result, for he knew of two previous experiments in which the rays had
apparently been deflected by electric fields. These experiments, by
Crookes and Goldstein in 1879 and 1880 respectively, used slightly
different apparatus, but the principle was the same. Two cathodes were
placed in the vacuum tube, and wired so they could be switched on or off
independently. With only one cathode active, the rays passed in a straight
line as usual, but when the second was swiched on, the two streams of rays
curved away from each other. Crookes said this showed that the rays were
negatively charged particles, which repelled each other and diverged as
they moved away from the cathodes. This explanation was disproved by
Wiedemann and Ebert in 1891, who showed that the deflection is in fact due
to the intense electric field surrounding the other cathode, not the rays
emanating from it. Once again, Crookes had come to the right conclusion
for the wrong reasons!
This experiment also explained why cathode rays are always emitted
normally from the surface of the cathode. The electric field next to any
perfect conductor is always perpendicular to its surface, and it is this
field that accelerates the rays away from the cathode. Hence the rays are
initially accelerated at right angles from the cathode, then deflected
according by the shape of the cathode or any other electrodes nearby.
Thomson repeated Hertz's experiment to deflect the rays, and
obtained the same result - the electric field between the plates did not
appear to make any difference to the path of the rays, however large he
made the voltage between the plates. The solution to this problem came
from Lenard's old observaion that cathode rays increase the electrical
conductivity of any gas which they pass through. Thomson related this to
his own experiments on gases ionised by X-rays, and concluded that cathode
rays too must generate charged gas molecules. If an electric field is set
up in a gas containing ions, the negative ions will move towards the
positive plate and the positive ions to the negative plate. This will
continue until enough ions have built up near the plates to balance out
the electric field due to the plates themselves. Of course some ions will
be discharged by collisions with the plates, but this will not occur fast
enough to prevent a layer of charged gas building up near the plates.
Hence after a short time the field due to the plates will not be felt at
all by the cathode rays, and they will not show any deflection.
To avoid this problem, the obvious solution was to pump away the
gas so there are no ions to build up on the plates. Thomson was lucky in
that the quality of vacuum pumps had greatly improved since Hertz's
experiments, and he was easily able to test his idea. As he predicted,
the conductivity of the gas dropped rapidly as the air was pumped out, and
the rays were deflected.
(intermediate pressures?)
Now there there were no known properties of the rays that could not
be explained in terms of particles. All that was left for Thomson to do
was to measure the deflections of the rays and calculate the physical
parameters of the particles, namely their velocity, charge and mass. One
attempt to measure the mass:charge ratio of the particles had already been
made by Schuster in the late 1880s, using the magnetic deflection alone as
follows The acceleration of a particle of mass m and charge e travelling
at speed v perpendicular to a magnetic field of magnitude B is given by
Bev
a = ---
m
and directed perpendicular to the velocity and magnetic field. This causes
the rays to travel in a circle of radius r, given by
2
v Bev mv
--- = --- so that r = --
r m Be
Thus by measuring the field B and radius of curvature r, Schuster
found a value for mv/e. To find the mass:charge ratio m/e from this, he
needed a value for the velocity v, which was not so easily measured and
had to be estimated. He did this by wrongly assuming that the particles in
the rays were in thermal equilibrium with the surrounding air molecules.
As Thomson points out this cannot possibly be the case, since the rays
would not travel in straight lines across the tube if they were all
reflecting from air molecules. From this assumption Schuster unfortunately
arrived at the conclusion that the rays must be streams of ionised air
molecules. When Hertz discovered that the rays could pass through solid
aluminium, the particle theory seemed to be in ridicule, since a stream
gas molecules could not possibly pass through an airtight seal and hardly
be attenuated! Some suggested that the impact of molecules on one side of
the sheet somehow stimulated a new emission of rays on the far side,
though it is not clear how this stimulus could travel through the metal.
In 1894 Thomson had obtained his own estimate for the velocity of
the cathode rays, by measuring the time lag between switching on the rays,
and the appearence of the phosphorescence on the end of the tube. This
approach was also flawed, since the time lag is in fact caused by a
process occurring on the phosphorescent surface, not by time needed for
the rays to arrive there. Hence his value for the velocity was again far
too small and the mass:charge ratio was too large.
In his paper of October 1897, Thomson admits that these previous
measurements of the velocity were useless, and he describes two better
methods. Both methods use Schuster's experiment to measure mv/e using the
deflection in a magnetic field, as described above. The methods differ in
how they obtain from this the velocity v and mass:charge ratio m/e.
In the first method, he measures the electric current carried by
the rays. This quantity I is given by
I = ne
where n is the number of particles passing along the rays per second. He
then made use of another well-known property of cathode rays, that they
heat up any surface they strike. Assuming that the particles stop dead
when they strike the surface, Thomson reasoned that the kinetic energy
carried by the particles per second would be equal to the heat W given to
to the surface per second. That is,
1 2
W = - nmv
2
2
Thus, 2W mv
-- = ---
I e
Dividing this quantity by mv/e, which he already knew, would give
the velocity v and hence the mass:charge ratio. Thomson measured the rate
of heating, W, using a thermocouple, and the current I by collecting the
rays in a cylinder connected to an electrometer as in Perrin's experiment.
The resulting values of m/e and v are tabulated in his paper in the
Philosophical Magazine, October 1897. The values of m/e vary through a
factor of about three between the different readings, though they are all
less than a thousanth of the value for the hydrogen ion (proton). This
seemed a very surprising, and perhaps suspicious result, since no particle
was thought to exist with such a small mass:charge ratio.
00000000 81 2e 2e 2e 2e 2e 2e 2e 2e 2e 2a 2e 2e 2e 2e 2e |..........*.....| 00000010 2e 2e 2a 2e 2e 2e 2e 2e 2e 2e 2a 2e 2e 2e 2e 2e |..*.......*.....| * 00000040 2e 2e 2a 2e 2e 2e 2e 2e 2e 2e 2a 2e 3c 0d 09 54 |..*.......*.<..T| 00000050 68 69 73 20 73 74 69 6c 6c 20 6c 65 66 74 20 74 |his still left t| 00000060 68 65 20 64 69 66 66 69 63 75 6c 74 79 20 74 68 |he difficulty th| 00000070 61 74 20 48 65 72 74 7a 20 68 61 64 20 66 61 69 |at Hertz had fai| 00000080 6c 65 64 20 74 6f 20 64 65 66 6c 65 63 74 20 74 |led to deflect t| 00000090 68 65 0d 63 61 74 68 6f 64 65 20 72 61 79 73 20 |he.cathode rays | 000000a0 62 79 20 61 70 70 6c 79 69 6e 67 20 61 6e 1a 20 |by applying an. | 000000b0 65 6c 65 63 74 72 69 63 1a 20 66 69 65 6c 64 2e |electric. field.| 000000c0 20 54 68 6f 6d 73 6f 6e 20 77 61 73 20 73 75 73 | Thomson was sus| 000000d0 70 69 63 69 6f 75 73 20 61 62 6f 75 74 0d 74 68 |picious about.th| 000000e0 69 73 20 72 65 73 75 6c 74 2c 20 66 6f 72 20 68 |is result, for h| 000000f0 65 20 6b 6e 65 77 20 6f 66 20 74 77 6f 20 70 72 |e knew of two pr| 00000100 65 76 69 6f 75 73 20 65 78 70 65 72 69 6d 65 6e |evious experimen| 00000110 74 73 20 69 6e 20 77 68 69 63 68 20 74 68 65 20 |ts in which the | 00000120 72 61 79 73 20 68 61 64 0d 61 70 70 61 72 65 6e |rays had.apparen| 00000130 74 6c 79 1a 20 62 65 65 6e 1a 20 64 65 66 6c 65 |tly. been. defle| 00000140 63 74 65 64 1a 20 62 79 1a 20 65 6c 65 63 74 72 |cted. by. electr| 00000150 69 63 1a 20 66 69 65 6c 64 73 2e 20 54 68 65 73 |ic. fields. Thes| 00000160 65 1a 20 65 78 70 65 72 69 6d 65 6e 74 73 2c 1a |e. experiments,.| 00000170 20 62 79 0d 43 72 6f 6f 6b 65 73 1a 20 61 6e 64 | by.Crookes. and| 00000180 1a 20 47 6f 6c 64 73 74 65 69 6e 1a 20 69 6e 1a |. Goldstein. in.| 00000190 20 31 38 37 39 20 61 6e 64 1a 20 31 38 38 30 1a | 1879 and. 1880.| 000001a0 20 72 65 73 70 65 63 74 69 76 65 6c 79 2c 1a 20 | respectively,. | 000001b0 75 73 65 64 1a 20 73 6c 69 67 68 74 6c 79 0d 64 |used. slightly.d| 000001c0 69 66 66 65 72 65 6e 74 20 61 70 70 61 72 61 74 |ifferent apparat| 000001d0 75 73 2c 20 62 75 74 20 74 68 65 20 70 72 69 6e |us, but the prin| 000001e0 63 69 70 6c 65 1a 20 77 61 73 1a 20 74 68 65 1a |ciple. was. the.| 000001f0 20 73 61 6d 65 2e 1a 20 54 77 6f 20 63 61 74 68 | same.. Two cath| 00000200 6f 64 65 73 20 77 65 72 65 0d 70 6c 61 63 65 64 |odes were.placed| 00000210 20 69 6e 20 74 68 65 20 76 61 63 75 75 6d 20 74 | in the vacuum t| 00000220 75 62 65 2c 20 61 6e 64 20 77 69 72 65 64 20 73 |ube, and wired s| 00000230 6f 20 74 68 65 79 1a 20 63 6f 75 6c 64 1a 20 62 |o they. could. b| 00000240 65 20 73 77 69 74 63 68 65 64 20 6f 6e 20 6f 72 |e switched on or| 00000250 20 6f 66 66 0d 69 6e 64 65 70 65 6e 64 65 6e 74 | off.independent| 00000260 6c 79 2e 20 57 69 74 68 20 6f 6e 6c 79 20 6f 6e |ly. With only on| 00000270 65 20 63 61 74 68 6f 64 65 20 61 63 74 69 76 65 |e cathode active| 00000280 2c 20 74 68 65 20 72 61 79 73 20 70 61 73 73 65 |, the rays passe| 00000290 64 20 69 6e 20 61 20 73 74 72 61 69 67 68 74 0d |d in a straight.| 000002a0 6c 69 6e 65 20 61 73 20 75 73 75 61 6c 2c 20 62 |line as usual, b| 000002b0 75 74 20 77 68 65 6e 20 74 68 65 20 73 65 63 6f |ut when the seco| 000002c0 6e 64 20 77 61 73 20 73 77 69 63 68 65 64 20 6f |nd was swiched o| 000002d0 6e 2c 20 74 68 65 20 74 77 6f 20 73 74 72 65 61 |n, the two strea| 000002e0 6d 73 20 6f 66 20 72 61 79 73 0d 63 75 72 76 65 |ms of rays.curve| 000002f0 64 20 61 77 61 79 20 66 72 6f 6d 20 65 61 63 68 |d away from each| 00000300 20 6f 74 68 65 72 2e 20 43 72 6f 6f 6b 65 73 20 | other. Crookes | 00000310 73 61 69 64 20 74 68 69 73 20 73 68 6f 77 65 64 |said this showed| 00000320 20 74 68 61 74 20 74 68 65 1a 20 72 61 79 73 1a | that the. rays.| 00000330 20 77 65 72 65 0d 6e 65 67 61 74 69 76 65 6c 79 | were.negatively| 00000340 1a 20 63 68 61 72 67 65 64 1a 20 70 61 72 74 69 |. charged. parti| 00000350 63 6c 65 73 2c 1a 20 77 68 69 63 68 20 72 65 70 |cles,. which rep| 00000360 65 6c 6c 65 64 20 65 61 63 68 20 6f 74 68 65 72 |elled each other| 00000370 20 61 6e 64 20 64 69 76 65 72 67 65 64 20 61 73 | and diverged as| 00000380 0d 74 68 65 79 20 6d 6f 76 65 64 20 61 77 61 79 |.they moved away| 00000390 20 66 72 6f 6d 1a 20 74 68 65 1a 20 63 61 74 68 | from. the. cath| 000003a0 6f 64 65 73 2e 1a 20 54 68 69 73 1a 20 65 78 70 |odes.. This. exp| 000003b0 6c 61 6e 61 74 69 6f 6e 1a 20 77 61 73 1a 20 64 |lanation. was. d| 000003c0 69 73 70 72 6f 76 65 64 20 62 79 0d 57 69 65 64 |isproved by.Wied| 000003d0 65 6d 61 6e 6e 20 61 6e 64 20 45 62 65 72 74 20 |emann and Ebert | 000003e0 69 6e 20 31 38 39 31 2c 20 77 68 6f 20 73 68 6f |in 1891, who sho| 000003f0 77 65 64 20 74 68 61 74 20 74 68 65 20 64 65 66 |wed that the def| 00000400 6c 65 63 74 69 6f 6e 20 69 73 20 69 6e 20 66 61 |lection is in fa| 00000410 63 74 20 64 75 65 0d 74 6f 20 74 68 65 20 69 6e |ct due.to the in| 00000420 74 65 6e 73 65 20 65 6c 65 63 74 72 69 63 20 66 |tense electric f| 00000430 69 65 6c 64 1a 20 73 75 72 72 6f 75 6e 64 69 6e |ield. surroundin| 00000440 67 20 74 68 65 20 6f 74 68 65 72 20 63 61 74 68 |g the other cath| 00000450 6f 64 65 2c 20 6e 6f 74 20 74 68 65 20 72 61 79 |ode, not the ray| 00000460 73 0d 65 6d 61 6e 61 74 69 6e 67 20 66 72 6f 6d |s.emanating from| 00000470 20 69 74 2e 20 4f 6e 63 65 20 61 67 61 69 6e 2c | it. Once again,| 00000480 20 43 72 6f 6f 6b 65 73 1a 20 68 61 64 1a 20 63 | Crookes. had. c| 00000490 6f 6d 65 1a 20 74 6f 20 74 68 65 20 72 69 67 68 |ome. to the righ| 000004a0 74 20 63 6f 6e 63 6c 75 73 69 6f 6e 0d 66 6f 72 |t conclusion.for| 000004b0 1a 20 74 68 65 20 77 72 6f 6e 67 20 72 65 61 73 |. the wrong reas| 000004c0 6f 6e 73 21 20 0d 09 54 68 69 73 20 65 78 70 65 |ons! ..This expe| 000004d0 72 69 6d 65 6e 74 20 61 6c 73 6f 20 65 78 70 6c |riment also expl| 000004e0 61 69 6e 65 64 20 77 68 79 1a 20 63 61 74 68 6f |ained why. catho| 000004f0 64 65 20 72 61 79 73 20 61 72 65 20 61 6c 77 61 |de rays are alwa| 00000500 79 73 20 65 6d 69 74 74 65 64 0d 6e 6f 72 6d 61 |ys emitted.norma| 00000510 6c 6c 79 20 66 72 6f 6d 20 74 68 65 20 73 75 72 |lly from the sur| 00000520 66 61 63 65 20 6f 66 20 74 68 65 1a 20 63 61 74 |face of the. cat| 00000530 68 6f 64 65 2e 1a 20 54 68 65 20 65 6c 65 63 74 |hode.. The elect| 00000540 72 69 63 20 66 69 65 6c 64 20 6e 65 78 74 20 74 |ric field next t| 00000550 6f 20 61 6e 79 0d 70 65 72 66 65 63 74 20 63 6f |o any.perfect co| 00000560 6e 64 75 63 74 6f 72 20 69 73 20 61 6c 77 61 79 |nductor is alway| 00000570 73 20 70 65 72 70 65 6e 64 69 63 75 6c 61 72 20 |s perpendicular | 00000580 74 6f 20 69 74 73 20 73 75 72 66 61 63 65 2c 1a |to its surface,.| 00000590 20 61 6e 64 1a 20 69 74 20 69 73 20 74 68 69 73 | and. it is this| 000005a0 0d 66 69 65 6c 64 20 74 68 61 74 20 61 63 63 65 |.field that acce| 000005b0 6c 65 72 61 74 65 73 20 74 68 65 20 72 61 79 73 |lerates the rays| 000005c0 20 61 77 61 79 20 66 72 6f 6d 20 74 68 65 20 63 | away from the c| 000005d0 61 74 68 6f 64 65 2e 20 48 65 6e 63 65 1a 20 74 |athode. Hence. t| 000005e0 68 65 20 72 61 79 73 20 61 72 65 0d 69 6e 69 74 |he rays are.init| 000005f0 69 61 6c 6c 79 1a 20 61 63 63 65 6c 65 72 61 74 |ially. accelerat| 00000600 65 64 1a 20 61 74 1a 20 72 69 67 68 74 1a 20 61 |ed. at. right. a| 00000610 6e 67 6c 65 73 20 66 72 6f 6d 20 74 68 65 20 63 |ngles from the c| 00000620 61 74 68 6f 64 65 2c 20 74 68 65 6e 20 64 65 66 |athode, then def| 00000630 6c 65 63 74 65 64 0d 61 63 63 6f 72 64 69 6e 67 |lected.according| 00000640 20 62 79 20 74 68 65 20 73 68 61 70 65 20 6f 66 | by the shape of| 00000650 20 74 68 65 20 63 61 74 68 6f 64 65 20 6f 72 20 | the cathode or | 00000660 61 6e 79 20 6f 74 68 65 72 20 65 6c 65 63 74 72 |any other electr| 00000670 6f 64 65 73 20 6e 65 61 72 62 79 2e 0d 09 20 54 |odes nearby... T| 00000680 68 6f 6d 73 6f 6e 1a 20 72 65 70 65 61 74 65 64 |homson. repeated| 00000690 1a 20 48 65 72 74 7a 27 73 20 65 78 70 65 72 69 |. Hertz's experi| 000006a0 6d 65 6e 74 20 74 6f 1a 20 64 65 66 6c 65 63 74 |ment to. deflect| 000006b0 1a 20 74 68 65 1a 20 72 61 79 73 2c 1a 20 61 6e |. the. rays,. an| 000006c0 64 0d 6f 62 74 61 69 6e 65 64 20 74 68 65 20 73 |d.obtained the s| 000006d0 61 6d 65 1a 20 72 65 73 75 6c 74 1a 20 2d 20 74 |ame. result. - t| 000006e0 68 65 20 65 6c 65 63 74 72 69 63 20 66 69 65 6c |he electric fiel| 000006f0 64 20 62 65 74 77 65 65 6e 20 74 68 65 20 70 6c |d between the pl| 00000700 61 74 65 73 20 64 69 64 20 6e 6f 74 0d 61 70 70 |ates did not.app| 00000710 65 61 72 20 74 6f 20 6d 61 6b 65 20 61 6e 79 20 |ear to make any | 00000720 64 69 66 66 65 72 65 6e 63 65 1a 20 74 6f 1a 20 |difference. to. | 00000730 74 68 65 1a 20 70 61 74 68 20 6f 66 20 74 68 65 |the. path of the| 00000740 20 72 61 79 73 2c 20 68 6f 77 65 76 65 72 20 6c | rays, however l| 00000750 61 72 67 65 20 68 65 0d 6d 61 64 65 20 74 68 65 |arge he.made the| 00000760 20 76 6f 6c 74 61 67 65 20 62 65 74 77 65 65 6e | voltage between| 00000770 20 74 68 65 20 70 6c 61 74 65 73 2e 20 54 68 65 | the plates. The| 00000780 20 73 6f 6c 75 74 69 6f 6e 1a 20 74 6f 1a 20 74 | solution. to. t| 00000790 68 69 73 1a 20 70 72 6f 62 6c 65 6d 1a 20 63 61 |his. problem. ca| 000007a0 6d 65 0d 66 72 6f 6d 1a 20 4c 65 6e 61 72 64 27 |me.from. Lenard'| 000007b0 73 1a 20 6f 6c 64 1a 20 6f 62 73 65 72 76 61 69 |s. old. observai| 000007c0 6f 6e 1a 20 74 68 61 74 20 63 61 74 68 6f 64 65 |on. that cathode| 000007d0 20 72 61 79 73 20 69 6e 63 72 65 61 73 65 20 74 | rays increase t| 000007e0 68 65 20 65 6c 65 63 74 72 69 63 61 6c 0d 63 6f |he electrical.co| 000007f0 6e 64 75 63 74 69 76 69 74 79 20 6f 66 20 61 6e |nductivity of an| 00000800 79 20 67 61 73 20 77 68 69 63 68 1a 20 74 68 65 |y gas which. the| 00000810 79 1a 20 70 61 73 73 20 74 68 72 6f 75 67 68 2e |y. pass through.| 00000820 20 54 68 6f 6d 73 6f 6e 20 72 65 6c 61 74 65 64 | Thomson related| 00000830 20 74 68 69 73 20 74 6f 0d 68 69 73 20 6f 77 6e | this to.his own| 00000840 20 65 78 70 65 72 69 6d 65 6e 74 73 20 6f 6e 20 | experiments on | 00000850 67 61 73 65 73 20 69 6f 6e 69 73 65 64 20 62 79 |gases ionised by| 00000860 20 58 2d 72 61 79 73 2c 20 61 6e 64 20 63 6f 6e | X-rays, and con| 00000870 63 6c 75 64 65 64 20 74 68 61 74 20 63 61 74 68 |cluded that cath| 00000880 6f 64 65 0d 72 61 79 73 20 74 6f 6f 20 6d 75 73 |ode.rays too mus| 00000890 74 20 67 65 6e 65 72 61 74 65 20 63 68 61 72 67 |t generate charg| 000008a0 65 64 20 67 61 73 20 6d 6f 6c 65 63 75 6c 65 73 |ed gas molecules| 000008b0 2e 1a 20 49 66 20 61 6e 20 65 6c 65 63 74 72 69 |.. If an electri| 000008c0 63 20 66 69 65 6c 64 20 69 73 20 73 65 74 0d 75 |c field is set.u| 000008d0 70 20 69 6e 20 61 20 67 61 73 20 63 6f 6e 74 61 |p in a gas conta| 000008e0 69 6e 69 6e 67 1a 20 69 6f 6e 73 2c 1a 20 74 68 |ining. ions,. th| 000008f0 65 1a 20 6e 65 67 61 74 69 76 65 1a 20 69 6f 6e |e. negative. ion| 00000900 73 1a 20 77 69 6c 6c 1a 20 6d 6f 76 65 20 74 6f |s. will. move to| 00000910 77 61 72 64 73 20 74 68 65 0d 70 6f 73 69 74 69 |wards the.positi| 00000920 76 65 1a 20 70 6c 61 74 65 1a 20 61 6e 64 1a 20 |ve. plate. and. | 00000930 74 68 65 1a 20 70 6f 73 69 74 69 76 65 1a 20 69 |the. positive. i| 00000940 6f 6e 73 20 74 6f 20 74 68 65 20 6e 65 67 61 74 |ons to the negat| 00000950 69 76 65 20 70 6c 61 74 65 2e 20 54 68 69 73 20 |ive plate. This | 00000960 77 69 6c 6c 0d 63 6f 6e 74 69 6e 75 65 20 75 6e |will.continue un| 00000970 74 69 6c 20 65 6e 6f 75 67 68 20 69 6f 6e 73 20 |til enough ions | 00000980 68 61 76 65 20 62 75 69 6c 74 1a 20 75 70 1a 20 |have built. up. | 00000990 6e 65 61 72 1a 20 74 68 65 20 70 6c 61 74 65 73 |near. the plates| 000009a0 20 74 6f 20 62 61 6c 61 6e 63 65 20 6f 75 74 0d | to balance out.| 000009b0 74 68 65 20 65 6c 65 63 74 72 69 63 20 66 69 65 |the electric fie| 000009c0 6c 64 20 64 75 65 20 74 6f 20 74 68 65 20 70 6c |ld due to the pl| 000009d0 61 74 65 73 20 74 68 65 6d 73 65 6c 76 65 73 2e |ates themselves.| 000009e0 20 4f 66 1a 20 63 6f 75 72 73 65 20 73 6f 6d 65 | Of. course some| 000009f0 20 69 6f 6e 73 20 77 69 6c 6c 0d 62 65 20 64 69 | ions will.be di| 00000a00 73 63 68 61 72 67 65 64 20 62 79 20 63 6f 6c 6c |scharged by coll| 00000a10 69 73 69 6f 6e 73 20 77 69 74 68 20 74 68 65 20 |isions with the | 00000a20 70 6c 61 74 65 73 2c 20 62 75 74 20 74 68 69 73 |plates, but this| 00000a30 20 77 69 6c 6c 1a 20 6e 6f 74 20 6f 63 63 75 72 | will. not occur| 00000a40 20 66 61 73 74 0d 65 6e 6f 75 67 68 1a 20 74 6f | fast.enough. to| 00000a50 1a 20 70 72 65 76 65 6e 74 1a 20 61 20 6c 61 79 |. prevent. a lay| 00000a60 65 72 20 6f 66 20 63 68 61 72 67 65 64 20 67 61 |er of charged ga| 00000a70 73 20 62 75 69 6c 64 69 6e 67 20 75 70 20 6e 65 |s building up ne| 00000a80 61 72 1a 20 74 68 65 1a 20 70 6c 61 74 65 73 2e |ar. the. plates.| 00000a90 0d 48 65 6e 63 65 20 61 66 74 65 72 20 61 20 73 |.Hence after a s| 00000aa0 68 6f 72 74 1a 20 74 69 6d 65 1a 20 74 68 65 20 |hort. time. the | 00000ab0 66 69 65 6c 64 20 64 75 65 20 74 6f 20 74 68 65 |field due to the| 00000ac0 20 70 6c 61 74 65 73 20 77 69 6c 6c 20 6e 6f 74 | plates will not| 00000ad0 20 62 65 20 66 65 6c 74 20 61 74 0d 61 6c 6c 20 | be felt at.all | 00000ae0 62 79 20 74 68 65 20 63 61 74 68 6f 64 65 20 72 |by the cathode r| 00000af0 61 79 73 2c 20 61 6e 64 20 74 68 65 79 20 77 69 |ays, and they wi| 00000b00 6c 6c 20 6e 6f 74 20 73 68 6f 77 20 61 6e 79 20 |ll not show any | 00000b10 64 65 66 6c 65 63 74 69 6f 6e 2e 20 0d 09 54 6f |deflection. ..To| 00000b20 20 61 76 6f 69 64 20 74 68 69 73 20 70 72 6f 62 | avoid this prob| 00000b30 6c 65 6d 2c 20 74 68 65 1a 20 6f 62 76 69 6f 75 |lem, the. obviou| 00000b40 73 1a 20 73 6f 6c 75 74 69 6f 6e 1a 20 77 61 73 |s. solution. was| 00000b50 20 74 6f 20 70 75 6d 70 20 61 77 61 79 20 74 68 | to pump away th| 00000b60 65 0d 67 61 73 20 73 6f 20 74 68 65 72 65 20 61 |e.gas so there a| 00000b70 72 65 20 6e 6f 20 69 6f 6e 73 20 74 6f 20 62 75 |re no ions to bu| 00000b80 69 6c 64 1a 20 75 70 1a 20 6f 6e 20 74 68 65 20 |ild. up. on the | 00000b90 70 6c 61 74 65 73 2e 20 54 68 6f 6d 73 6f 6e 20 |plates. Thomson | 00000ba0 77 61 73 20 6c 75 63 6b 79 20 69 6e 0d 74 68 61 |was lucky in.tha| 00000bb0 74 1a 20 74 68 65 1a 20 71 75 61 6c 69 74 79 1a |t. the. quality.| 00000bc0 20 6f 66 1a 20 76 61 63 75 75 6d 1a 20 70 75 6d | of. vacuum. pum| 00000bd0 70 73 1a 20 68 61 64 1a 20 67 72 65 61 74 6c 79 |ps. had. greatly| 00000be0 20 69 6d 70 72 6f 76 65 64 20 73 69 6e 63 65 20 | improved since | 00000bf0 48 65 72 74 7a 27 73 0d 65 78 70 65 72 69 6d 65 |Hertz's.experime| 00000c00 6e 74 73 2c 20 61 6e 64 20 68 65 20 77 61 73 20 |nts, and he was | 00000c10 65 61 73 69 6c 79 20 61 62 6c 65 20 74 6f 20 74 |easily able to t| 00000c20 65 73 74 1a 20 68 69 73 1a 20 69 64 65 61 2e 1a |est. his. idea..| 00000c30 20 41 73 1a 20 68 65 20 70 72 65 64 69 63 74 65 | As. he predicte| 00000c40 64 2c 20 0d 74 68 65 20 63 6f 6e 64 75 63 74 69 |d, .the conducti| 00000c50 76 69 74 79 20 6f 66 20 74 68 65 20 67 61 73 20 |vity of the gas | 00000c60 64 72 6f 70 70 65 64 20 72 61 70 69 64 6c 79 20 |dropped rapidly | 00000c70 61 73 20 74 68 65 20 61 69 72 20 77 61 73 20 70 |as the air was p| 00000c80 75 6d 70 65 64 20 6f 75 74 2c 20 61 6e 64 0d 74 |umped out, and.t| 00000c90 68 65 20 72 61 79 73 20 77 65 72 65 20 64 65 66 |he rays were def| 00000ca0 6c 65 63 74 65 64 2e 0d 0d 28 69 6e 74 65 72 6d |lected...(interm| 00000cb0 65 64 69 61 74 65 20 70 72 65 73 73 75 72 65 73 |ediate pressures| 00000cc0 3f 29 0d 0d 09 4e 6f 77 20 74 68 65 72 65 20 74 |?)...Now there t| 00000cd0 68 65 72 65 20 77 65 72 65 20 6e 6f 20 6b 6e 6f |here were no kno| 00000ce0 77 6e 20 70 72 6f 70 65 72 74 69 65 73 20 6f 66 |wn properties of| 00000cf0 20 74 68 65 20 72 61 79 73 20 74 68 61 74 20 63 | the rays that c| 00000d00 6f 75 6c 64 20 6e 6f 74 0d 62 65 20 65 78 70 6c |ould not.be expl| 00000d10 61 69 6e 65 64 20 69 6e 20 74 65 72 6d 73 20 6f |ained in terms o| 00000d20 66 1a 20 70 61 72 74 69 63 6c 65 73 2e 1a 20 41 |f. particles.. A| 00000d30 6c 6c 1a 20 74 68 61 74 20 77 61 73 20 6c 65 66 |ll. that was lef| 00000d40 74 20 66 6f 72 20 54 68 6f 6d 73 6f 6e 20 74 6f |t for Thomson to| 00000d50 20 64 6f 0d 77 61 73 1a 20 74 6f 20 6d 65 61 73 | do.was. to meas| 00000d60 75 72 65 20 74 68 65 20 64 65 66 6c 65 63 74 69 |ure the deflecti| 00000d70 6f 6e 73 20 6f 66 20 74 68 65 20 72 61 79 73 1a |ons of the rays.| 00000d80 20 61 6e 64 1a 20 63 61 6c 63 75 6c 61 74 65 1a | and. calculate.| 00000d90 20 74 68 65 1a 20 70 68 79 73 69 63 61 6c 0d 70 | the. physical.p| 00000da0 61 72 61 6d 65 74 65 72 73 20 6f 66 1a 20 74 68 |arameters of. th| 00000db0 65 1a 20 70 61 72 74 69 63 6c 65 73 2c 20 6e 61 |e. particles, na| 00000dc0 6d 65 6c 79 20 74 68 65 69 72 20 76 65 6c 6f 63 |mely their veloc| 00000dd0 69 74 79 2c 20 63 68 61 72 67 65 20 61 6e 64 20 |ity, charge and | 00000de0 6d 61 73 73 2e 20 4f 6e 65 0d 61 74 74 65 6d 70 |mass. One.attemp| 00000df0 74 20 74 6f 20 6d 65 61 73 75 72 65 20 74 68 65 |t to measure the| 00000e00 20 6d 61 73 73 3a 63 68 61 72 67 65 20 72 61 74 | mass:charge rat| 00000e10 69 6f 20 6f 66 20 74 68 65 20 70 61 72 74 69 63 |io of the partic| 00000e20 6c 65 73 20 68 61 64 20 61 6c 72 65 61 64 79 20 |les had already | 00000e30 62 65 65 6e 0d 6d 61 64 65 20 62 79 20 53 63 68 |been.made by Sch| 00000e40 75 73 74 65 72 20 69 6e 20 74 68 65 20 6c 61 74 |uster in the lat| 00000e50 65 20 31 38 38 30 73 2c 20 75 73 69 6e 67 20 74 |e 1880s, using t| 00000e60 68 65 20 6d 61 67 6e 65 74 69 63 20 64 65 66 6c |he magnetic defl| 00000e70 65 63 74 69 6f 6e 20 61 6c 6f 6e 65 20 61 73 0d |ection alone as.| 00000e80 66 6f 6c 6c 6f 77 73 20 54 68 65 20 61 63 63 65 |follows The acce| 00000e90 6c 65 72 61 74 69 6f 6e 20 6f 66 1a 20 61 1a 20 |leration of. a. | 00000ea0 70 61 72 74 69 63 6c 65 20 6f 66 20 6d 61 73 73 |particle of mass| 00000eb0 20 6d 20 61 6e 64 20 63 68 61 72 67 65 20 65 20 | m and charge e | 00000ec0 74 72 61 76 65 6c 6c 69 6e 67 0d 61 74 20 73 70 |travelling.at sp| 00000ed0 65 65 64 20 76 20 70 65 72 70 65 6e 64 69 63 75 |eed v perpendicu| 00000ee0 6c 61 72 20 74 6f 20 61 20 6d 61 67 6e 65 74 69 |lar to a magneti| 00000ef0 63 20 66 69 65 6c 64 20 6f 66 20 6d 61 67 6e 69 |c field of magni| 00000f00 74 75 64 65 20 42 20 69 73 20 67 69 76 65 6e 20 |tude B is given | 00000f10 62 79 0d 09 09 09 42 65 76 0d 09 09 20 20 20 20 |by....Bev... | 00000f20 61 20 3d 09 2d 2d 2d 0d 09 09 09 20 6d 20 20 20 |a =.---.... m | 00000f30 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 | | 00000f40 20 20 20 20 20 20 20 20 20 0d 61 6e 64 20 64 69 | .and di| 00000f50 72 65 63 74 65 64 20 70 65 72 70 65 6e 64 69 63 |rected perpendic| 00000f60 75 6c 61 72 20 74 6f 20 74 68 65 20 76 65 6c 6f |ular to the velo| 00000f70 63 69 74 79 20 61 6e 64 20 6d 61 67 6e 65 74 69 |city and magneti| 00000f80 63 20 66 69 65 6c 64 2e 20 54 68 69 73 20 63 61 |c field. This ca| 00000f90 75 73 65 73 0d 74 68 65 20 72 61 79 73 20 74 6f |uses.the rays to| 00000fa0 20 74 72 61 76 65 6c 20 69 6e 20 61 20 63 69 72 | travel in a cir| 00000fb0 63 6c 65 20 6f 66 20 72 61 64 69 75 73 20 72 2c |cle of radius r,| 00000fc0 20 67 69 76 65 6e 20 62 79 0d 20 20 20 20 20 20 | given by. | 00000fd0 20 20 20 20 20 20 20 20 20 20 20 20 20 32 0d 09 | 2..| 00000fe0 09 20 20 20 76 20 20 20 20 42 65 76 20 20 20 20 |. v Bev | 00000ff0 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 6d | m| 00001000 76 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |v. | 00001010 20 20 20 2d 2d 2d 20 3d 20 2d 2d 2d 20 20 20 20 | --- = --- | 00001020 73 6f 20 74 68 61 74 20 20 20 20 72 20 3d 20 2d |so that r = -| 00001030 2d 0d 20 20 20 20 20 20 20 20 20 20 20 20 20 20 |-. | 00001040 20 20 20 20 72 20 20 20 20 20 6d 20 20 20 20 20 | r m | 00001050 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 42 | B| 00001060 65 0d 09 54 68 75 73 20 62 79 20 6d 65 61 73 75 |e..Thus by measu| 00001070 72 69 6e 67 20 74 68 65 20 66 69 65 6c 64 1a 20 |ring the field. | 00001080 42 1a 20 61 6e 64 20 72 61 64 69 75 73 20 6f 66 |B. and radius of| 00001090 20 63 75 72 76 61 74 75 72 65 20 72 2c 20 53 63 | curvature r, Sc| 000010a0 68 75 73 74 65 72 0d 66 6f 75 6e 64 20 61 20 76 |huster.found a v| 000010b0 61 6c 75 65 20 66 6f 72 20 6d 76 2f 65 2e 20 54 |alue for mv/e. T| 000010c0 6f 20 66 69 6e 64 1a 20 74 68 65 1a 20 6d 61 73 |o find. the. mas| 000010d0 73 3a 63 68 61 72 67 65 1a 20 72 61 74 69 6f 20 |s:charge. ratio | 000010e0 6d 2f 65 20 66 72 6f 6d 20 74 68 69 73 2c 20 68 |m/e from this, h| 000010f0 65 0d 6e 65 65 64 65 64 20 61 20 76 61 6c 75 65 |e.needed a value| 00001100 20 66 6f 72 20 74 68 65 20 76 65 6c 6f 63 69 74 | for the velocit| 00001110 79 20 76 2c 20 77 68 69 63 68 20 77 61 73 20 6e |y v, which was n| 00001120 6f 74 1a 20 73 6f 1a 20 65 61 73 69 6c 79 1a 20 |ot. so. easily. | 00001130 6d 65 61 73 75 72 65 64 20 61 6e 64 0d 68 61 64 |measured and.had| 00001140 20 74 6f 20 62 65 20 65 73 74 69 6d 61 74 65 64 | to be estimated| 00001150 2e 20 48 65 20 64 69 64 20 74 68 69 73 20 62 79 |. He did this by| 00001160 20 77 72 6f 6e 67 6c 79 20 61 73 73 75 6d 69 6e | wrongly assumin| 00001170 67 20 74 68 61 74 20 74 68 65 20 70 61 72 74 69 |g that the parti| 00001180 63 6c 65 73 20 69 6e 0d 74 68 65 1a 20 72 61 79 |cles in.the. ray| 00001190 73 1a 20 77 65 72 65 20 69 6e 20 74 68 65 72 6d |s. were in therm| 000011a0 61 6c 20 65 71 75 69 6c 69 62 72 69 75 6d 20 77 |al equilibrium w| 000011b0 69 74 68 20 74 68 65 20 73 75 72 72 6f 75 6e 64 |ith the surround| 000011c0 69 6e 67 20 61 69 72 20 6d 6f 6c 65 63 75 6c 65 |ing air molecule| 000011d0 73 2e 0d 41 73 20 54 68 6f 6d 73 6f 6e 20 70 6f |s..As Thomson po| 000011e0 69 6e 74 73 1a 20 6f 75 74 1a 20 74 68 69 73 1a |ints. out. this.| 000011f0 20 63 61 6e 6e 6f 74 1a 20 70 6f 73 73 69 62 6c | cannot. possibl| 00001200 79 20 62 65 20 74 68 65 20 63 61 73 65 2c 20 73 |y be the case, s| 00001210 69 6e 63 65 20 74 68 65 20 72 61 79 73 0d 77 6f |ince the rays.wo| 00001220 75 6c 64 1a 20 6e 6f 74 20 74 72 61 76 65 6c 20 |uld. not travel | 00001230 69 6e 20 73 74 72 61 69 67 68 74 20 6c 69 6e 65 |in straight line| 00001240 73 20 61 63 72 6f 73 73 1a 20 74 68 65 1a 20 74 |s across. the. t| 00001250 75 62 65 1a 20 69 66 1a 20 74 68 65 79 1a 20 77 |ube. if. they. w| 00001260 65 72 65 1a 20 61 6c 6c 0d 72 65 66 6c 65 63 74 |ere. all.reflect| 00001270 69 6e 67 20 66 72 6f 6d 20 61 69 72 20 6d 6f 6c |ing from air mol| 00001280 65 63 75 6c 65 73 2e 20 46 72 6f 6d 20 74 68 69 |ecules. From thi| 00001290 73 20 61 73 73 75 6d 70 74 69 6f 6e 20 53 63 68 |s assumption Sch| 000012a0 75 73 74 65 72 20 75 6e 66 6f 72 74 75 6e 61 74 |uster unfortunat| 000012b0 65 6c 79 0d 61 72 72 69 76 65 64 20 61 74 1a 20 |ely.arrived at. | 000012c0 74 68 65 1a 20 63 6f 6e 63 6c 75 73 69 6f 6e 1a |the. conclusion.| 000012d0 20 74 68 61 74 1a 20 74 68 65 20 72 61 79 73 20 | that. the rays | 000012e0 6d 75 73 74 20 62 65 20 73 74 72 65 61 6d 73 20 |must be streams | 000012f0 6f 66 20 69 6f 6e 69 73 65 64 20 61 69 72 0d 6d |of ionised air.m| 00001300 6f 6c 65 63 75 6c 65 73 2e 20 57 68 65 6e 20 48 |olecules. When H| 00001310 65 72 74 7a 20 64 69 73 63 6f 76 65 72 65 64 20 |ertz discovered | 00001320 74 68 61 74 20 74 68 65 1a 20 72 61 79 73 1a 20 |that the. rays. | 00001330 63 6f 75 6c 64 1a 20 70 61 73 73 20 74 68 72 6f |could. pass thro| 00001340 75 67 68 20 73 6f 6c 69 64 0d 61 6c 75 6d 69 6e |ugh solid.alumin| 00001350 69 75 6d 2c 20 74 68 65 20 70 61 72 74 69 63 6c |ium, the particl| 00001360 65 20 74 68 65 6f 72 79 20 73 65 65 6d 65 64 20 |e theory seemed | 00001370 74 6f 20 62 65 20 69 6e 20 72 69 64 69 63 75 6c |to be in ridicul| 00001380 65 2c 1a 20 73 69 6e 63 65 1a 20 61 1a 20 73 74 |e,. since. a. st| 00001390 72 65 61 6d 0d 67 61 73 1a 20 6d 6f 6c 65 63 75 |ream.gas. molecu| 000013a0 6c 65 73 20 63 6f 75 6c 64 20 6e 6f 74 20 70 6f |les could not po| 000013b0 73 73 69 62 6c 79 20 70 61 73 73 20 74 68 72 6f |ssibly pass thro| 000013c0 75 67 68 20 61 6e 20 61 69 72 74 69 67 68 74 20 |ugh an airtight | 000013d0 73 65 61 6c 20 61 6e 64 20 68 61 72 64 6c 79 0d |seal and hardly.| 000013e0 62 65 20 61 74 74 65 6e 75 61 74 65 64 21 1a 20 |be attenuated!. | 000013f0 53 6f 6d 65 20 73 75 67 67 65 73 74 65 64 20 74 |Some suggested t| 00001400 68 61 74 20 74 68 65 20 69 6d 70 61 63 74 20 6f |hat the impact o| 00001410 66 20 6d 6f 6c 65 63 75 6c 65 73 20 6f 6e 20 6f |f molecules on o| 00001420 6e 65 20 73 69 64 65 20 6f 66 0d 74 68 65 20 73 |ne side of.the s| 00001430 68 65 65 74 20 73 6f 6d 65 68 6f 77 1a 20 73 74 |heet somehow. st| 00001440 69 6d 75 6c 61 74 65 64 1a 20 61 1a 20 6e 65 77 |imulated. a. new| 00001450 1a 20 65 6d 69 73 73 69 6f 6e 1a 20 6f 66 1a 20 |. emission. of. | 00001460 72 61 79 73 20 6f 6e 20 74 68 65 20 66 61 72 20 |rays on the far | 00001470 73 69 64 65 2c 0d 74 68 6f 75 67 68 20 69 74 20 |side,.though it | 00001480 69 73 20 6e 6f 74 20 63 6c 65 61 72 20 68 6f 77 |is not clear how| 00001490 20 74 68 69 73 20 73 74 69 6d 75 6c 75 73 20 63 | this stimulus c| 000014a0 6f 75 6c 64 20 74 72 61 76 65 6c 20 74 68 72 6f |ould travel thro| 000014b0 75 67 68 20 74 68 65 20 6d 65 74 61 6c 2e 0d 09 |ugh the metal...| 000014c0 49 6e 20 31 38 39 34 20 54 68 6f 6d 73 6f 6e 20 |In 1894 Thomson | 000014d0 68 61 64 20 6f 62 74 61 69 6e 65 64 1a 20 68 69 |had obtained. hi| 000014e0 73 1a 20 6f 77 6e 20 65 73 74 69 6d 61 74 65 20 |s. own estimate | 000014f0 66 6f 72 20 74 68 65 20 76 65 6c 6f 63 69 74 79 |for the velocity| 00001500 20 6f 66 0d 74 68 65 20 63 61 74 68 6f 64 65 20 | of.the cathode | 00001510 72 61 79 73 2c 20 62 79 20 6d 65 61 73 75 72 69 |rays, by measuri| 00001520 6e 67 20 74 68 65 20 74 69 6d 65 20 6c 61 67 20 |ng the time lag | 00001530 62 65 74 77 65 65 6e 20 73 77 69 74 63 68 69 6e |between switchin| 00001540 67 20 6f 6e 20 74 68 65 20 72 61 79 73 2c 0d 61 |g on the rays,.a| 00001550 6e 64 20 74 68 65 20 61 70 70 65 61 72 65 6e 63 |nd the appearenc| 00001560 65 20 6f 66 20 74 68 65 20 70 68 6f 73 70 68 6f |e of the phospho| 00001570 72 65 73 63 65 6e 63 65 20 6f 6e 1a 20 74 68 65 |rescence on. the| 00001580 1a 20 65 6e 64 1a 20 6f 66 1a 20 74 68 65 20 74 |. end. of. the t| 00001590 75 62 65 2e 20 54 68 69 73 0d 61 70 70 72 6f 61 |ube. This.approa| 000015a0 63 68 1a 20 77 61 73 20 61 6c 73 6f 20 66 6c 61 |ch. was also fla| 000015b0 77 65 64 2c 20 73 69 6e 63 65 20 74 68 65 20 74 |wed, since the t| 000015c0 69 6d 65 20 6c 61 67 1a 20 69 73 1a 20 69 6e 1a |ime lag. is. in.| 000015d0 20 66 61 63 74 1a 20 63 61 75 73 65 64 1a 20 62 | fact. caused. b| 000015e0 79 1a 20 61 0d 70 72 6f 63 65 73 73 1a 20 6f 63 |y. a.process. oc| 000015f0 63 75 72 72 69 6e 67 1a 20 6f 6e 1a 20 74 68 65 |curring. on. the| 00001600 20 70 68 6f 73 70 68 6f 72 65 73 63 65 6e 74 20 | phosphorescent | 00001610 73 75 72 66 61 63 65 2c 20 6e 6f 74 20 62 79 20 |surface, not by | 00001620 74 69 6d 65 20 6e 65 65 64 65 64 20 66 6f 72 0d |time needed for.| 00001630 74 68 65 20 72 61 79 73 20 74 6f 20 61 72 72 69 |the rays to arri| 00001640 76 65 1a 20 74 68 65 72 65 2e 1a 20 48 65 6e 63 |ve. there.. Henc| 00001650 65 20 68 69 73 20 76 61 6c 75 65 20 66 6f 72 20 |e his value for | 00001660 74 68 65 20 76 65 6c 6f 63 69 74 79 20 77 61 73 |the velocity was| 00001670 20 61 67 61 69 6e 20 66 61 72 0d 74 6f 6f 20 73 | again far.too s| 00001680 6d 61 6c 6c 20 61 6e 64 20 74 68 65 20 6d 61 73 |mall and the mas| 00001690 73 3a 63 68 61 72 67 65 20 72 61 74 69 6f 20 77 |s:charge ratio w| 000016a0 61 73 20 74 6f 6f 20 6c 61 72 67 65 2e 0d 09 49 |as too large...I| 000016b0 6e 20 68 69 73 20 70 61 70 65 72 20 6f 66 20 4f |n his paper of O| 000016c0 63 74 6f 62 65 72 1a 20 31 38 39 37 2c 1a 20 54 |ctober. 1897,. T| 000016d0 68 6f 6d 73 6f 6e 1a 20 61 64 6d 69 74 73 20 74 |homson. admits t| 000016e0 68 61 74 20 74 68 65 73 65 20 70 72 65 76 69 6f |hat these previo| 000016f0 75 73 0d 6d 65 61 73 75 72 65 6d 65 6e 74 73 1a |us.measurements.| 00001700 20 6f 66 20 74 68 65 20 76 65 6c 6f 63 69 74 79 | of the velocity| 00001710 20 77 65 72 65 20 75 73 65 6c 65 73 73 2c 20 61 | were useless, a| 00001720 6e 64 20 68 65 1a 20 64 65 73 63 72 69 62 65 73 |nd he. describes| 00001730 1a 20 74 77 6f 1a 20 62 65 74 74 65 72 0d 6d 65 |. two. better.me| 00001740 74 68 6f 64 73 2e 20 42 6f 74 68 1a 20 6d 65 74 |thods. Both. met| 00001750 68 6f 64 73 20 75 73 65 20 53 63 68 75 73 74 65 |hods use Schuste| 00001760 72 27 73 20 65 78 70 65 72 69 6d 65 6e 74 20 74 |r's experiment t| 00001770 6f 20 6d 65 61 73 75 72 65 20 6d 76 2f 65 20 75 |o measure mv/e u| 00001780 73 69 6e 67 20 74 68 65 0d 64 65 66 6c 65 63 74 |sing the.deflect| 00001790 69 6f 6e 20 69 6e 20 61 1a 20 6d 61 67 6e 65 74 |ion in a. magnet| 000017a0 69 63 20 66 69 65 6c 64 2c 20 61 73 20 64 65 73 |ic field, as des| 000017b0 63 72 69 62 65 64 20 61 62 6f 76 65 2e 20 54 68 |cribed above. Th| 000017c0 65 20 6d 65 74 68 6f 64 73 20 64 69 66 66 65 72 |e methods differ| 000017d0 20 69 6e 0d 68 6f 77 20 74 68 65 79 20 6f 62 74 | in.how they obt| 000017e0 61 69 6e 20 66 72 6f 6d 20 74 68 69 73 20 74 68 |ain from this th| 000017f0 65 20 76 65 6c 6f 63 69 74 79 20 76 20 61 6e 64 |e velocity v and| 00001800 20 6d 61 73 73 3a 63 68 61 72 67 65 20 72 61 74 | mass:charge rat| 00001810 69 6f 20 6d 2f 65 2e 0d 09 49 6e 20 74 68 65 20 |io m/e...In the | 00001820 66 69 72 73 74 20 6d 65 74 68 6f 64 2c 20 68 65 |first method, he| 00001830 1a 20 6d 65 61 73 75 72 65 73 1a 20 74 68 65 1a |. measures. the.| 00001840 20 65 6c 65 63 74 72 69 63 20 63 75 72 72 65 6e | electric curren| 00001850 74 20 63 61 72 72 69 65 64 20 62 79 0d 74 68 65 |t carried by.the| 00001860 20 72 61 79 73 2e 20 54 68 69 73 20 71 75 61 6e | rays. This quan| 00001870 74 69 74 79 20 49 20 69 73 20 67 69 76 65 6e 20 |tity I is given | 00001880 62 79 0d 09 09 20 49 20 3d 20 6e 65 0d 77 68 65 |by... I = ne.whe| 00001890 72 65 20 6e 20 69 73 20 74 68 65 20 6e 75 6d 62 |re n is the numb| 000018a0 65 72 1a 20 6f 66 1a 20 70 61 72 74 69 63 6c 65 |er. of. particle| 000018b0 73 20 70 61 73 73 69 6e 67 20 61 6c 6f 6e 67 20 |s passing along | 000018c0 74 68 65 20 72 61 79 73 20 70 65 72 20 73 65 63 |the rays per sec| 000018d0 6f 6e 64 2e 20 48 65 0d 74 68 65 6e 20 6d 61 64 |ond. He.then mad| 000018e0 65 20 75 73 65 20 6f 66 20 61 6e 6f 74 68 65 72 |e use of another| 000018f0 20 77 65 6c 6c 2d 6b 6e 6f 77 6e 20 70 72 6f 70 | well-known prop| 00001900 65 72 74 79 1a 20 6f 66 1a 20 63 61 74 68 6f 64 |erty. of. cathod| 00001910 65 1a 20 72 61 79 73 2c 20 74 68 61 74 20 74 68 |e. rays, that th| 00001920 65 79 0d 68 65 61 74 1a 20 75 70 1a 20 61 6e 79 |ey.heat. up. any| 00001930 20 73 75 72 66 61 63 65 20 74 68 65 79 20 73 74 | surface they st| 00001940 72 69 6b 65 2e 20 41 73 73 75 6d 69 6e 67 20 74 |rike. Assuming t| 00001950 68 61 74 20 74 68 65 20 70 61 72 74 69 63 6c 65 |hat the particle| 00001960 73 1a 20 73 74 6f 70 1a 20 64 65 61 64 0d 77 68 |s. stop. dead.wh| 00001970 65 6e 20 74 68 65 79 20 73 74 72 69 6b 65 1a 20 |en they strike. | 00001980 74 68 65 1a 20 73 75 72 66 61 63 65 2c 1a 20 54 |the. surface,. T| 00001990 68 6f 6d 73 6f 6e 1a 20 72 65 61 73 6f 6e 65 64 |homson. reasoned| 000019a0 20 74 68 61 74 20 74 68 65 20 6b 69 6e 65 74 69 | that the kineti| 000019b0 63 20 65 6e 65 72 67 79 0d 63 61 72 72 69 65 64 |c energy.carried| 000019c0 20 62 79 20 74 68 65 20 70 61 72 74 69 63 6c 65 | by the particle| 000019d0 73 20 70 65 72 20 73 65 63 6f 6e 64 20 77 6f 75 |s per second wou| 000019e0 6c 64 1a 20 62 65 20 65 71 75 61 6c 20 74 6f 20 |ld. be equal to | 000019f0 74 68 65 20 68 65 61 74 20 57 20 67 69 76 65 6e |the heat W given| 00001a00 20 74 6f 0d 74 6f 20 74 68 65 20 73 75 72 66 61 | to.to the surfa| 00001a10 63 65 20 70 65 72 20 73 65 63 6f 6e 64 2e 20 54 |ce per second. T| 00001a20 68 61 74 20 69 73 2c 0d 20 20 20 20 20 20 20 20 |hat is,. | 00001a30 20 20 20 20 20 20 20 20 20 20 20 31 20 20 20 20 | 1 | 00001a40 32 0d 09 09 57 20 3d 20 2d 20 6e 6d 76 0d 09 09 |2...W = - nmv...| 00001a50 20 20 20 20 32 0d 20 20 20 20 20 20 20 20 20 20 | 2. | 00001a60 20 20 20 20 20 20 20 20 20 20 20 32 0d 09 54 68 | 2..Th| 00001a70 75 73 2c 20 20 32 57 20 20 20 6d 76 0d 09 20 20 |us, 2W mv.. | 00001a80 20 20 20 20 20 2d 2d 20 3d 20 2d 2d 2d 0d 09 09 | -- = ---...| 00001a90 49 20 20 20 20 65 0d 09 44 69 76 69 64 69 6e 67 |I e..Dividing| 00001aa0 20 74 68 69 73 20 71 75 61 6e 74 69 74 79 20 62 | this quantity b| 00001ab0 79 20 6d 76 2f 65 2c 1a 20 77 68 69 63 68 1a 20 |y mv/e,. which. | 00001ac0 68 65 20 61 6c 72 65 61 64 79 20 6b 6e 65 77 2c |he already knew,| 00001ad0 20 77 6f 75 6c 64 20 67 69 76 65 0d 74 68 65 20 | would give.the | 00001ae0 76 65 6c 6f 63 69 74 79 20 76 20 61 6e 64 20 68 |velocity v and h| 00001af0 65 6e 63 65 20 74 68 65 20 6d 61 73 73 3a 63 68 |ence the mass:ch| 00001b00 61 72 67 65 1a 20 72 61 74 69 6f 2e 20 54 68 6f |arge. ratio. Tho| 00001b10 6d 73 6f 6e 20 6d 65 61 73 75 72 65 64 20 74 68 |mson measured th| 00001b20 65 20 72 61 74 65 0d 6f 66 20 68 65 61 74 69 6e |e rate.of heatin| 00001b30 67 2c 20 57 2c 20 75 73 69 6e 67 20 61 20 74 68 |g, W, using a th| 00001b40 65 72 6d 6f 63 6f 75 70 6c 65 2c 20 61 6e 64 20 |ermocouple, and | 00001b50 74 68 65 1a 20 63 75 72 72 65 6e 74 1a 20 49 20 |the. current. I | 00001b60 62 79 20 63 6f 6c 6c 65 63 74 69 6e 67 20 74 68 |by collecting th| 00001b70 65 0d 72 61 79 73 20 69 6e 20 61 20 63 79 6c 69 |e.rays in a cyli| 00001b80 6e 64 65 72 20 63 6f 6e 6e 65 63 74 65 64 20 74 |nder connected t| 00001b90 6f 20 61 6e 20 65 6c 65 63 74 72 6f 6d 65 74 65 |o an electromete| 00001ba0 72 20 61 73 20 69 6e 20 50 65 72 72 69 6e 27 73 |r as in Perrin's| 00001bb0 20 65 78 70 65 72 69 6d 65 6e 74 2e 0d 54 68 65 | experiment..The| 00001bc0 1a 20 72 65 73 75 6c 74 69 6e 67 1a 20 76 61 6c |. resulting. val| 00001bd0 75 65 73 1a 20 6f 66 20 6d 2f 65 20 61 6e 64 20 |ues. of m/e and | 00001be0 76 20 61 72 65 20 74 61 62 75 6c 61 74 65 64 20 |v are tabulated | 00001bf0 69 6e 1a 20 68 69 73 1a 20 70 61 70 65 72 1a 20 |in. his. paper. | 00001c00 69 6e 1a 20 74 68 65 0d 50 68 69 6c 6f 73 6f 70 |in. the.Philosop| 00001c10 68 69 63 61 6c 20 4d 61 67 61 7a 69 6e 65 2c 20 |hical Magazine, | 00001c20 4f 63 74 6f 62 65 72 20 31 38 39 37 2e 1a 20 54 |October 1897.. T| 00001c30 68 65 1a 20 76 61 6c 75 65 73 1a 20 6f 66 1a 20 |he. values. of. | 00001c40 6d 2f 65 20 76 61 72 79 20 74 68 72 6f 75 67 68 |m/e vary through| 00001c50 20 61 0d 66 61 63 74 6f 72 20 6f 66 20 61 62 6f | a.factor of abo| 00001c60 75 74 20 74 68 72 65 65 20 62 65 74 77 65 65 6e |ut three between| 00001c70 1a 20 74 68 65 20 64 69 66 66 65 72 65 6e 74 20 |. the different | 00001c80 72 65 61 64 69 6e 67 73 2c 20 74 68 6f 75 67 68 |readings, though| 00001c90 20 74 68 65 79 20 61 72 65 20 61 6c 6c 0d 6c 65 | they are all.le| 00001ca0 73 73 20 74 68 61 6e 20 61 20 74 68 6f 75 73 61 |ss than a thousa| 00001cb0 6e 74 68 20 6f 66 20 74 68 65 1a 20 76 61 6c 75 |nth of the. valu| 00001cc0 65 1a 20 66 6f 72 1a 20 74 68 65 1a 20 68 79 64 |e. for. the. hyd| 00001cd0 72 6f 67 65 6e 20 69 6f 6e 20 28 70 72 6f 74 6f |rogen ion (proto| 00001ce0 6e 29 2e 20 54 68 69 73 0d 73 65 65 6d 65 64 20 |n). This.seemed | 00001cf0 61 20 76 65 72 79 20 73 75 72 70 72 69 73 69 6e |a very surprisin| 00001d00 67 2c 20 61 6e 64 20 70 65 72 68 61 70 73 20 73 |g, and perhaps s| 00001d10 75 73 70 69 63 69 6f 75 73 20 72 65 73 75 6c 74 |uspicious result| 00001d20 2c 20 73 69 6e 63 65 20 6e 6f 20 70 61 72 74 69 |, since no parti| 00001d30 63 6c 65 0d 77 61 73 20 74 68 6f 75 67 68 74 20 |cle.was thought | 00001d40 74 6f 20 65 78 69 73 74 20 77 69 74 68 20 73 75 |to exist with su| 00001d50 63 68 20 61 20 73 6d 61 6c 6c 20 6d 61 73 73 3a |ch a small mass:| 00001d60 63 68 61 72 67 65 20 72 61 74 69 6f 2e 0d |charge ratio..| 00001d6e
EltronBKP/ElectronC.m0
EltronBKP/ElectronC.m1
EltronBKP/ElectronC.m2
EltronBKP/ElectronC.m4
EltronBKP/ElectronC.m5
.