222 



Mr. William Sutherland on the 



that is with an internal virial varying inversely as the volume 

 down to near the critical volume, and Jlvf\v) tending some- 

 where near that point to about double its value in the perfect 

 gas state. The course of Rvf(v) in these four gases is repre- 

 sented by the simple form 



which attains the value 2R when v = k. 

 teristic equation down to v = k is 



/ - 



pv = UT 1+ — 



\ v — 



Hence the charac- 



a form which I had already adopted for air (Phil. Mag. Aug. 



1887). The following are the values for k and I : — 

 H. N 2 . 2 . CH 4 . Air. 



k . . 12-0 2-64 1-78 5*51 2'47[2^11] 

 I . . 41700 1175 851 6460 1110[910] 



The values given in brackets for air are those previously 

 found by me from Amagat's data (Compt. Rend, xcix.), but as 

 these data are not carried to such high pressures as those for 

 "N" 2 and 2 , I have calculated values for air by adding to four 

 fifths of the values for N 2 one fifth of the values for 2 . 



This equation is almost identical with that of Yan der 

 Waals, but it is a little simpler. It gives the following pres- 

 sures for comparison with Amagat's experimental results : — 



Table X. 



Hydrogen. 



At 17-7° 0. 



V. 



p exp. 



1669 



100-1 



601 



46-7 



57-5 



99 

 176 

 238 



56" 



99 

 176 

 241 



At 100° C. 



669 



74-2 



004 



129 



601 



230 



467 



311 



73-3 

 128 

 229 

 315 



Nitrogen. 



At 17-7° C. 



13-83 

 6-91 

 461 

 3 69 

 3-23 



p exp. 



46 



92 

 145 

 194 

 223 



At 100 C. 



p calc. 



13-83 



60 



691 



125 



4-61 



200 



3 69 



270 



3-23 



320 



45-7 



91 

 142 

 188 

 9;?(\ 



60-5 

 124 

 199 

 266 

 323 



Oxygen. 

 At 14-7° C. 



5 73 

 3-58 

 2-58 

 243 



p exp. 



141 



201 

 216 



p calc 



At 100° C. 



5-73 



123 



3-58 



204 



2-58 



300 



2-43 



322 



89-7 

 142 

 203 

 219 



124 

 204 

 301 

 327 



