92 Prof. H. L. Callendar on the Thermodynamical 



and expansion-coefficients of the other gases are deduced on 

 the assumption O = 273°*1O. 



Table XIII. 

 Expansion- and Pressure-Coefficients of Diatomic Gases. 



Constant-Pressure. 76 cms. 

 G-as | 



Constant-Volume, p = 100 cms. 



1 

 i employed. j 9 — T . 



To. 



1/T . 



o _T o- 



T . 1/T . 



Air 071 



Nitrogen ... 070 

 Hydrogen ... — -135 



272-39 



272-40 

 273235 



•0036709 

 •0036708 

 •00365985 



o 



0-96 



0-99 



+ -067 



27214 -00367425 



27241 -00367466 



1 

 273-034 : -00366254 



Regnault's values of the expansion-coefficient for hydrogen 

 at 76 cms. range from -0036642 to '0036586. Chappuis at 

 100 cms. finds "0036600 for hydrogen at constant pressure, 

 and -0036726 to -0036735 for nitrogen, the calculated values 

 being -0036593 and '0036737 respectively. 



The values of the thermodynamical corrections for the 

 diatomic gases are calculated by the following formulae : — 



Assuming rc = l*5, c = c (d lQ) 1,5 , c — c 1 = , 3738c . 



Zero-Correction G. P., 



6> -T = (c -b + 2-73 x -374 x c ) /> /R. 

 Zero-Correction C. V., 



6> -T = 3-73x '374.x Copo/R. 

 Scale-Correction C. P., 



^=(0-3738 t/lOO-l+{0 o /ey' s )c Q p o /R,. 

 Scale-Correction C. V., 



^ = (0-1445 */100-l+ {d /Oy 5 )c oP JR. 



The densities of oxygen and nitrogen at the boiling-point of 

 oxygen at a pressure of 760 mm. have been directly deter- 

 mined by Dewar (Proc. Roy. Soc. lxix. p. 360) by the method 

 of weighing. The resulting values of the specific volumes 

 were: — Oxygen, v = 225*8 c. c. per gramme, Nitrogen, z*= 

 256*8 c. c. at 90 o, 5 Abs. with a possible error of 0*5 per cent. 

 The ideal volumes at this temperature and pressure are: — - 

 Oxygen, 231*8 c. c, Nitrogen, 264*9 c. c. The values of c — b 

 at 90°*5 Abs. are : Oxygen, c — 6 = 6*0 c. c. ; Nitrogen, 



