166 HOW CROPS FEED. 
cury to cool. Then introduced into the various gases 
named below, it absorbed as many times its bulk of them, 
as are designated by the subjoined figures: 
AMMONIW: soared cocrene cand 90 Hydrochloric acid....... 85 
Sulphurous acid......... 65 Hydrosulphuric acid..... 55 
Protoxide of nitrogen....40 Carbonic acid............ 35 
OXY SCN ss se eaey cede FeesGs 94% Carbonic oxide.......... 914 
Hydrogen............0006 134 Nitrogen; cisc0is seguats sees V6 
According to De Saussure, the absorption was complete 
in 24 hours, except in case of oxygen, where it continued for 
a long time, though with decreasing energy. The oxygen 
thus condensed in the charcoal combined with the carbon 
of the latter, forming carbonic acid. 
Stenhouse more lately has experimented in the same di- 
rection. From these researches we learn that the power 
in question is exerted towards different gases with very 
unequal effect, and that different kinds of charcoal exert 
very different condensing power. 
Stenhouse found that one gramme of dry charcoal ab- 
sorbed of several gases the number of cubic centimeters 
given below. 
Kind of Charcoal. 
Name of Gas. 
Wood. | Peat. | Animal. 
AMMO siece ss go cciase os sac ands ae eas eeiz eae 98.5 96.0 43.5 
Hydrochloric acid.......... 2.66. cesses cee enee 45.0 60.0 
Hydrosulphuric acid....... cece eee eee ewes 30.0 28.5 90 
Suiphurois aCidss cee cecases ci pexweeypieee sence 82.5 27.5 17.5 
Cay0010 ROG success sates Hx EV RRe ded cew wen 14.0 10.0 5.0 
ORY CCD einaseieis seca jest dinid oacasadeor he. eedisiciaie shea arsiemnaiainie 0.8 0.6 0.5 
The absorption or solution of gases in water, alcohol, 
and other liquids, is analogous to this condensation, and 
those gases which are most condensed by charcoal are in 
general, though not invariably, those which dissolve most 
copiously in liquids, (ammonia, hydrochloric acid). 
Condensation of Gases by the Soil.—Reichardt and 
Blumtritt have recently made a minute study of the kind 
and amount of gases that are condensed in the pores of 
various solid substances, including soils and some of their 
