connected with its Surface Tension. 151 
‘dation the relations that can be obtaimed from the fundamental 
equations the writer deduced from the law of molecular attraction. 
Some of these relations will be pointed out here. 
From the equations * 
me eu 2 6, Be Pi 
Nae (2) Se), ee m (?:) (2a) 
we have ; r=D, es SE ap SCAU NEAR Fd ORS (2), 
m® 
where m denotes the molecular weight relative to hydrogen, and 
_D, is a quantity which is the same for all substances at corre- 
_ sponding states. 
The equation + 
p= ar (2) (Sea) 
and one of the foregoing equations give 
m3 m\> 
nr = D, (=) = D (=| oun c cence etrccces 3 5 
P pi 3De om (3) 
where D, and D, are corresponding quantities, p denotes the 
pressure of the saturated vapour, and the suffix c indicates that 
the quantity to which it is attached refers to the critical point. 
_ The coefficient of compression 8 is given by 
where a, is a corresponding quantity, and hence equation (2) 
may be written 
where D, is a corresponding quantity. 
The coefficient of expansion a is given by 
ae COL 
iid pal 
By means of this equation and the equation 
RT .p. 
Po 3 Im 
equation (3) may be written 
8 
Pi 
i (22) ee ridbns ya ae (5), 
where D, is a corresponding quantity. 
* Phil. Mag. Oct. 1909, pp. 491—510. 
+ Ibid. Dec. 1909, p. 903. 
