Dolbear. | 
186 
[ Jan. 21, 
dynamics that, the kinetic energy of molecules is proportionate to 
absolute temperature. If temperature be absolute zero, then no 
work would be needed to separate atoms in a chemical compound, 
which is the same as saying that chemism does not exist at absolute 
zero. 1 This indicates plainly enough that chemism depends upon 
heat and one must therefore inquire into the specific nature of 
heat in order to discover if possible how it happens that it condi- 
tions the existence of chemism. 2 
For many years it has been common to speak of heat as a mode 
of motion, but before the invention of the spectroscope it was 
quite impossible to say whether the motion represented by the 
temperature of a body was a true vibratory motion or an oscilla- 
tion, swinging in space to and fro, or a rotation. Now we know 
that both atoms and molecules at any temperature vibrate in har- 
monic rates when not interfered with as is the case in a gas. 
Stoney long ago pointed out that the C. F. and H. hydrogen lines 
in the spectrum are the 20tli, 27th and 32nd harmonies of a funda- 
mental having a length .01312mm. 3 Knowing that the velocity 
of light divided by wave length gives the number of vibrations 
per second, it follows that 1_ ’ 1 = 22 4- 10 12 which 
r .01312 T 
is the number of fundamental vibrations per second an atom of 
hydrogen can make when free. 
1 Maxwell’s “ Theory of heat’’ pp. 160,161. 
H h 
— — & and T are the absolute temperatui’es of the hot and cold bodies in 
b T 
Carnot’s Engine, II and li are the quantities of heat taken up and given out. When 
T=0, then h=o, h being the heat equivalent of the work done. As this is o at abso- 
lute zero no work could be done in changing the volume of a substance at that temper- 
ature. There can be no cohesion among the molecules or atoms. It is the tempera- 
ture of dissociation. 
-2 This is the conclusion to which chemists have been led by their researches. For 
example Dr. Lothar Meyer says, “ At the lowest temperatures to which we can attain, 
the majority of chemical reactions studied under these conditions have been found to 
cease entirely or to proceed very slowly, so that it would appear to be very probable 
that at the absolute zero, viz. — 273° a temperature much below the lowest yet attained, 
chemical action would altogether cease, from the absence of any form of heat motion 
whatsoever. So without heat there would be no exertion of the so-called affinity.” 
“ Modern Theories of Chemistry,’’ § 211. 
3 It is not here asserted that atoms and molecules vibrate in simple harmonic series 
as do stretched strings and pipes, but that the ratios of the periods of vibration may be 
expressed by integer numbers. In Weid. Ann. xxv, p. 80 (1885), E. J. Balmer pre- 
sents such a law, and subsequent spectroscopic work, especially at Johns Hopkins Uni- 
versity gives great countenance to it. 
