428 
T.ORT) RAYLEIGH ON THE LAW OF THE PRESSLTtE OF GASES 
To = T 4 , In the smaU terms we expand in powers of the small temperatures 
(t, t), and farther identify B (H, + with 2 . The five terms on the right then 
assume the form 
^ {(m + /3) (tj — Tg — 2 t2 + 2t^) 4- /8®{2t2^ — 2t/ — 
+ /3) (r, - r,) - - r,^)] 
“ f J (^3 “ ^1) + /3 (^3 ~ tj) + „ ^^2)1 
_j_ 4^^ il I I _ /SV/] 
-^ {] — mxg — /3^3 + ^%~], 
in which on/S and are neglected, while /3' is detained. In j^oint of fact, the terms 
of the second degree were seldom sensible. 
Taking the data above given for the observations on air October 28—November 5, 
we find 
Term in Vg . 
. Vg . . . 
(V. - v;) 
(Va - Va') 
-- --000012 
= —-000002 
= +-000034 
= +-000652 
= --000103 
+-000569 
For the first term on the left of (6), we find 
so that 
_ 1 _ 
(1 - TOTi)(l + /3^i) 
1-000256 ; 
B = 
AhHafl + + ^0,) 
Vo(H, + H^) 
X -999687, 
or when the numerical values are introduced from (4), (5), 
B = 1-00002. 
The deviation from Boyle’s law is quite imperceptible. 
It may be noted that a value of B exceeding unity indicates an excessive com¬ 
pressibility, such as is manifested by carbonic acid under a pressure of a few 
atmospheres. 
