464 MR. S. CHAPMAN ON THE KINETIC THEORY OF A GAS 



WINKELMANN'S* value (T0000568 and MuLLER'st value 0'00005G. MEHLISSJ obtained 

 0-000038 for argon. 



SCHULTZE determined the following values of MO for argon and helium, using the 

 same materials as SCHWARZE : 



Argon 0'0002104, Helium 0'0001891. 

 Using the following values of C c : 



Argonl 0'0740, Helium|| 0'7142, 

 SCHWARZE thus finds these values of/: 



Argon 2-501, Helium 2'507. 



I proceed to discuss briefly the case of polyatomic gases. It is immediately obvious 

 that the present theory does not apply here, for G v in actual fact differs widely from 

 its value for the monatomic gas contemplated in the foregoing calculations (this is 

 not to say that /is not equal to -ij- for any polyatomic gas, but merely that our theory 

 leaves the question perfectly open). The same remark applies to any theory which 

 supposes the molecules to be devoid of internal energy in particular to MEYER'S 

 theory. But the latter has derived all its support from polyatomic gases. MEYER'S 

 views on this point underwent some changes. In 1877** he seems reluctantly to have 

 accepted the theory (strongly upheld by STEFAN and BOLTZMANN) that the internal 

 and translational molecular energies travelled at different rates (the latter most 

 rapidly), so that the conductivity would be less for a gas whose molecules possess 

 much atomic energy than, for a similar gas with little atomic energy. 



In 1899,tt however, he held that the conductivity is the same for both kinds of 

 energy, and supported this view by an unsound argument based on the law ot 

 equipartition. This enabled him to assert that / is equal to T6027 for all gases, and 

 so obtain all possible support from the data for polyatomic gases. More modern data 

 would give much less support to the theory, as we shall see. But such disproof is 

 unnecessary, for SCHWARZE'S experiments conclusively show (i) that MEYER'S value 



* ' WIED. Ann.,' 48, p. 180, 1893. 



t Ibid., 60, p. 82, 1897. 



J ' Halle Diss.,' 1902. 



' Halle Diss.,' 1901 ; ' Ann. d. Phys.,' 5, p. 140, 1901, and 6, p. 302, 1901. 



|| Calculated from the formula fR/Jni ; m = 0-1439 for the helium used, and J was taken as 427. 

 This leads to the above value of /, given in ' Ann. d. Phys.,' 11, p. 303, 1903. In ' Phys. Zeitschrift,' 8, 

 p. 229, 1903, J was taken as 424, which made / = 2-490. 



f C c for argon is calculated from C p (determined as 0-1233 by DITTEXBERGER, 'Halle Diss.,' 1897) 

 and 7 (determined as 1-667 by NIEMEYER, cf. 'Smithsonian Physical Tables,' 1910, p. 232). Thus 

 Cfjy = 0-0002104. 



** 'Kinetic Theory of Gases,' 1st edition, 1877. 



ft Ibid, 2nd edition, English translation, 1899, pp. 291-296. 



