440 W. A. Norton—Force of hffective Molecular Action. 
consequent greater liability to expansion under the operation 
of the heat energy. For olefiant gas we have aaa = 1-674; 
and 1°674x24=4-2, the theoretical value of & for this gas. 
These results enable us to test our expression for the ratio of 
the specific heats under a constant volume, and at a constant 
pressure, viz: <_ For the mixture of oxygen and hydrogen 
oe =1-430. The experimental value is 1410. For 
carbon-dioxide SO Bee According to experi- 
42+1 
1 =124, 
the same as obtained by experiment. For oxide of carbon I 
get £=2:60 and ratio of specific heats =1-38 ; experiment gives 
1-428. For oxide of nitrogen k=3-396 and ratio of specific 
heats =1:294; experiment gives 1348. 
Professor J. Clerk Maxwell (Nature, March 10, 1875, p. 375) 
admits that the kinetic theory of gases has encountered a serious 
dilemma in the attempt to determine specific heats. He says, 
“We lear from the spectroscope that a molecule can execute 
vibrations of constant period. It cannot therefore be a mere 
material point, but a system capable of changing its form. 
Such a system cannot have less than six variables. . . . But 
the spectroscope tells us that some molecules can execute a great 
many different kinds of vibrations. They must therefore be 
systems of a very considerable degree of complexity, having 
far more than six variables;” and ‘every additional variable 
increases the specific heat, whether reckoned at constant pres- 
sure or at constant volume. But the calculated specific heat 1s 
already too great when we suppose the molecule to consist of 
two atoms only.” The present theory encounters no such diffi- 
culty, since it regards the heat and light vibrations as pertaining 
to the atoms of the molecular envelopes, and the number of 
these is indefinitely great, and the determination of the specific 
eat requires no hypothesis of a definite number of atoms to 
be made. In the same connection Professor Maxwell has the 
following remark: “ And here we are brought face to face with 
the greatest difficulty which the molecular theory has yet 
encountered, namely, the interpretation of n+e=4°9. He had 
previously remarked “ that n+e, for air and several other gases, 
_ cannot be more than 49. For carbonic acid (?) and steam it 1s 
greater.” Now n+e answers to the ratio, &, on the present 
ment it is 1338. For olefiant gas the ratio is 
and le than 4-9 for the ¢ 
: theory, and we have seen (p. 483) that this is 4°93 for steam, 
