W. A. Norton—Force of Effective Molecular Action. 488 
Art. LVL—On the Force of ptt ee Action ; by 
Professor W. A 
[Continued from page 358.] 
For the eritical curve the molecular repulsion has very 
m 
nearly the constant value, 000524, from a=8r to e=7%r; 
and according to Dr. Andrews, the pressure of condensation 
at the critical point for carbonic acid gas was seventy-five 
atmospheres. These data give for the molecular repulsion 
0-0052~ m 
answering to one atmosphere, 7 =000006938—. This 
5 
phase then be the value Ag the minimum repulsive ordinate, 
obtains when x=38r, in the curve for water at the point of 
ebullition (212° F.). This result gives for this curve k=4‘931. 
distance. “Haier the effective molecules of he steam, 115r, 
and putting y= distance of the inner surface of the effective 
aavilail from the center of the molecule, I have 
1157r+2r+2y : : 
ar aa 8/1581; 
which gives y=2°76r. This calculation proceeds on the sup- 
position that the effective molecules have the same size in the 
va ane rous as in the liquid state, but theoretically they should 
e larger ; and we shall see in the sequel that _ probable 
value of the diameter of the molecules of steam is 42-257. If 
we adopt this estimate, the ratio of expansion by ‘oluie 1581 
Hy 1, gives for the diameter of the liquid molecule at 212° F., 
0-5r. 
Let us now see how far the well known laws of gases may be 
deduced from our molecular formula. 
(1). Avogadro's Law, relative to the simple posed) that all 
Simple gases contain in the same volume, at the sa 
and temperature, the same number of ultimate gps ja 
This law follows from the fact that for the large distances 
between contiguous molecules, that obtain in gases, the effec- 
together with the large size of the effective gaseous molecules 
The entire possible range of value for &, for gases and vapors, 
is from 0 to 4984; since it is only between these limits that 
the effective molecular force is repulsive at all a We 
Am. Joor. ee Series, Vou. XVII, No. 102.—Junz, 
