Specific Heat of a Gas with Temperature. 359 



so that 



J. ^ c= Ur) {i* + 4^ + 4j, ' '^j 

 /2R0\ 5 - 2 fl ,_** 3 -31 _,,\* 



The integral 



I </>.^6-=l <f>.dc.— \ (fy.dc 

 Jo Jo Jc 



Equation (2) now becomes 



2 ^ r2R0 f :) y /^ 

 v \/tt ~d~0 L m \ ' 8 



+ IgA- + ;^ + |^)}] 



3R r, 8<?E -II I,,...-. Ui. , 



+ iB-M-* + A H - W }].. . . (3) 



where E= 9R' 



Eucken t has determined experimentally the molecular 

 heat of hydrogen at low temperatures, and he obtains the 

 very important result that at very low temperatures the gas 

 behaves as if it were monatomic. Some of his values are 

 given below : — 



Oabs. ... 35 40 45 50 60 65 70 80 90 100 110 196-5 273 

 mol. ht.... 2-98 2-98 3"00 301 2-99 3-04 3*10 314 326 3-42 3-62 4-39 4*84 



If we put E = G25 and q = 2 in equation (3), we get the 

 following results : — 



9 abs 9 36 64 81 100 121 144 196 256 



K+(--). 1000 1-000 1-009 1-043 1-113 1-215 1-335 1-542 1-677 



v \2 m) 



* See Todd & Owen, Phil. Mag. vol. xxxvii. p. 227. 



t Eucken, Sitzunysber. kon. preuss. Akad. Wis&enschaft. 1912. 



