Quantity of Gases absorbed by Water , &c. 3$ 
But, 4|- inches of water were expelled, owing to the expansion 
by heat. Therefore, 117^ — 4^ = 113 inches of water, gave 
5.38 inches of gas; and 100 inches, consequently, gave 4.76, 
of which 3.38 were carbonic acid, and 1.38 atmospherical air. 
Hence, the water afforded about f- its bulk of atmospherical 
air, and ^ of a mixture of gases. In this estimate, the gas 
remaining in the tube is reckoned as carbonic acid, which may 
be allowed, since the portion last obtained held only ~ its bulk 
of common air. 
SECTION II. 
ON THE INFLUENCE OF PRESSURE IN PROMOTING THE ABSORP- 
TION OF GASES; AND THE DESCRIPTION OF AN APPARATUS 
FOR EXHIBITING THIS PHENOMENON. 
For the purpose of determining the ratio between the addi- 
tion of pressure and the increased absorption of gases by water, 
I employed the apparatus, with some addition, which has been 
already described. The tube B was lengthened at pleasure, with 
the view of obtaining, by a column of mercury, any additional 
pressure that might be required. The vessel A* Fig. 1, was 
then filled completely with mercury, which rose to its corre- 
sponding level in the tube B. A given quantity of water, of a 
known temperature, and afterwards a measured volume of gas, 
were transferred into the vessel, in the mode already described? 
and, as the mercury, by opening the cock b> was brought to the 
same level in both legs of the syphon, the gas, it is evident, 
must have been under the ordinary weight of the atmosphere. 
A quantity of mercury was next poured into the leg B, sufficient 
to form a column 28 inches higher than the level of the mer- 
cury in A, after this addition ; and the bulk of the gas was 
again noted. This was found to be, pretty exactly, f, •§-, &c. of 
