Prerrud) un the Absorption of the Gases. 834 
Artice II. 
Observations on the Alsorption of the Gases by different Bodies. 
By Theodore de Saussure. 
(Concluded from p. 255.) 
Secrion SECOND. 
SIMULTANEOUS ABSORPTION OF DIFFERENT GASES BY A SINGLE 
SOLID POROUS BODY. 
-Tur experiments hitherto made relate to the absorption of a 
single gas not mixed with any other. I come now to the more in- 
tricate problem, to examine whether when various gases have been 
absorbed by a porous solid body, their absorption corresponds with 
that which takes place when the gases are in a separate state. I 
have made these experiments two different ways: 1. I put the solid 
body freed from air into a mixture of two gases. 2. I brought the 
solid body first in contact with a single gas ; and when it was satu- 
rated with this gas, I transferred it into a second gas. The eudio- 
metrical examination of the air remaining behind after this second 
absorption enabled me to know the proportion in which both gases 
had been absorbed. 
7. Condensation of mixed Gases by Charcoal. 
Messrs. Rouppe and Norden have informed us (Ann. de Chim. 
t. 34) that when charcoal, saturated at the common temperature 
with hydrogen, is put into oxygen gas, water is seen condensing 
itself on the sides of the receiver in drops, whereby heat is disen- 
gaged, and oxygen gas absorbed. ‘Che same thing takes place, 
according to their statement, when the experiment is reversed, by 
introducing charcoal saturated with oxygen gas into hydrogen gas. 
In these assertions, which have-never been contradicted, there is 
nothing contrary to the generally received opinions. It is reason- 
,able to think that the condensation which the gases experience in 
the charcoal facilitate the union of their bases. It is therefore quite 
contrary to my expectation that I see myself obliged to call in ques- 
tion the statement of these Dutch chemists. 
1 made my experiments with oxygen gas, hydrogen gas, axotie 
gas, and carbonic acid gas, mixed together two and two. For the 
sake of perspicuity, I shall first state the general results which I 
obtained, and then enter into more particular details, in order to 
show which of the gases in these experiments was absorbed in the 
greatest quantity. 
(A)—When a piece of charcoal saturated with one of these gases 
is put into another, it allows a portion of the first gas to escape, in 
order to absorb into its pores a portion of the second gas, 
According asthe condensation of the gas first absorbed by the 
