1815.) — the Gases by different Bodies. 4) 249 
this stone, even when it seems perfectly dry, always contains some 
water, I put it first into the fire, and then introduced it under the 
air-pump while still warm. Having freed it from its air, J intro- 
duced it first into ammoniacal gas, and ascertained how much of 
this gas it absorbed. This experiment I repeated with the same 
piece of meerschaum for each of the other gases, first putting it 
into the fire, then introducing it under the air-pump, and lastly 
putting it into the gas to be absorbed; so that the same piece of 
meerschaum was brought successively in contact with all the gases. 
The size of the meerschaum was 2+ cubic inches; and this size 
made it possible for me to observe small variations in the absorption. 
A repetition of these experiments, the same way, and with the same 
piece of meerschaum, gave similar results. The following table 
exhibits the mean of these two sets of experiments, giving the 
number of volumes of each gas absorbed by one volume of the 
meerschaum at the temperature of 59°, and under a pressure of 
28-74 inches of mercury. 
Volumes. 
Ammoniacal gas*.....cccccccseeve 15 
Sulphureted hydrogen ...........606 117 
Carbonic acid gast ..+esseececseeee 526 
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OXYGEN. FAS -osrcvecvcncesseareper | 1°49 
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Oxy-carbureted hydrogen............ 0°85 
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As these absorptions were produced and destroyed by means of 
the air-pump alone, without the help of fire, this is a proof that 
the gases contract no union with the stone, which is equivalent to 
the atmospherical pressure. Besides, in these experiments, as in 
those with charcoal, no alterations in the temperature or barometrical 
took place. 
I repeated these experiments with another piece of meerschaum 
from Valecas, It produced a smaller absorption. When dried in 
the air, it absorbed three volumes, and when heated to redness only 
21 volumes, of carbonic acid gas. 
Meerschaum, like charcoal, absorbs a greater bulk of rare than 
dense gas. ‘Thus a mass of meerschaum of the bulk 13°87 absorbed, 
* When the meerschaum is employed as dry as it can be procured in the common 
temperature of the atmosphere, but without being heated red-hot, it absorbs 15 
volumes of awmoniacal gas, but requites (o do that several days, On the con- 
trary, when it has been heated to redness, the absorption is completed in five or 
six hours, Charcoal gives asimilar result, It follows from my experiments that 
a very small proportion of water greatly increases the power of meerschaum to 
absorb carbonic acid gas, but a great proportion of water diminishes that power, 
The aborption of carbonic acid gas is always slower when the meerschaum con- 
tains water than when itis dry. 
+ When the meerschaum was not heated to redness, the absorption of carbonic 
acid gus amounted to 13 volumes, 
