84 
MR. J. J. M^ATERSTON ON A GENERAL LAW 
The vapours of ether, alcohol, and sulphuret of carbon were tiied in the same way, and 
found to conform to the same law. I have since added to the Chart M. Avogadro’s 
observations on the vapour of mercury, which will be found remarkably in accord- 
ance; also Dr. Faraday’s experiments on liquefied gases, given in the Philosophical 
Transactions for 1845. Of these, olefiant gas (No. 1, p. 160) is remarkably in accord- 
ance; also the nitrous oxide (No. 2, p. 168), ammonia, cyanogen, sulphurous acid, 
and carbonic acid at the upper part of its range. Muriatic acid, sulphuretted and 
arseniuretted hydrogen do not show the same regularity. 
The coordinates of the points being the square root of the G temperature and 
the sixth root of the densities, the equation to the straight line that passes through 
the points expresses the sixth root of the density in terms of the square root of the G 
temperature. 
Thus let #,= the G temperature corre- 
sponding to Ai density of vapour: set off 
AC=\//i and CD =4^ A,. A second ob- 
servation treated in the same way gives 
AE, EF, which determines the position of 
the line of vapour BF. Thus let AC=^, 
and cotFBE=/<=^=|T^5^| and 
g=AB=v^i“"^^'^ ^1- 
The constants g and h are thus determined from two observations, and the equa 
tion for the density A at any other G temperature is 
t 
and for the pressure. 
h 
h 
( 2 .) 
(3.) 
The following are the equations for the series of observations given on the Chart ; 
the G temperatures are in degrees of Fahr. scale, and the values given to h are made 
to give the pressure in inches of mercury. 
Mercury (Avogadro) 
Oil of turpentine (Ure). 
Salt water saturated (Watt). 
Water (French Academy and Southern) 
j)=t 
p=zt 
V'#— 22*606'!® 
20*00 j ■ 
19*492]® 
10*830 j ' 
Alcohol, sp. gr. *813 (Ure) . 
19*287]® 
9*800 J * 
Sulphuret of carbon (Marx) 
Sulphuric ether (Dalton) . 
p=t 
p—t 
if -16*254]® 
1276 J ‘ 
16*860]® 
10*990 J ‘ 
