322 Sir H. Davy’s new experiments on some 
tions for 1810, show that the proportional or equivalent 
volume in which chlorine combines, is to that in which oxygen 
combines, as 2 to 1 ; and it follows, that 10 grains of phos- 
phorus in forming the white sublimate, or perchloride, ought to 
combine with between 7 6 and 80 cubical inches of chlorine. 
In experiments that I formerly made on this subject, by 
admitting chlorine to phosphorus in exhausted vessels, and 
ascertaining the absorption by introducing solution of chlorine, 
I overrated the absorption. I did not at that time know, what 
I have since ascertained, that a solution of chlorine in water, 
apparently saturated with chlorine, by agitation with it in long 
narrow vessels, will still take up more, by exposure to a great 
surface of chlorine in larger vessels. Under all circum- 
stances, it is difficult to gain very precise results in experi- 
ments on the action of phosphorus on chlorine. Mercury 
acts so rapidly upon chlorine, that it cannot be employed in 
experiments in which the absorption is to be determined. 
When common water is used, some of the gas is absorbed by 
the water, and, the sublimate being a very volatile substance, 
its vapour always increases the volume of the residual gas. 
Some aqueous vapour likewise, in experiments over water, 
enters with the gas, which forms a volatile hydrate, the 
effect of which is likewise to diminish the apparent absorp- 
tion of chlorine, 
I have always found the absorption greatest, when I have 
operated in small retorts, connected by small stop-cocks with 
the vessel containing the chlorine, over water. Making the 
proper corrections for the absorption by the water, the appa- 
rent absorption has been from 35 to 38 cubical inches for 
every 5 grains of phosphorus. 
