365 
of the power of carbonic acid in decomposing mineral substances, as 
feldspar, lime, &c., I consider it is highly probable that one of the chief 
advantages of ploughing under green crops will be owing to the action 
of carbonic acid on mineral substances in the soil, gradually decompos¬ 
ing them, and setting free their potash, lime, &c. 
"Two chemists, Wiegmann and PolstorfF, subjected white sand to the 
action of a boiling mixture of hydrochloric and nitric acid, and having 
washed aAvay all traces of the acid liquid, they digested the purified 
sand in distilled water, saturated with carbonic acid gas. At the expira- 
ration of thirty days, the water was filtered and evaporated to dryness, 
when a residue was obtained consisting of silica and carbonate of potash, 
with some lime and magnesia.” The experiment, as Prof. Way remarks, 
is highly significant, as showing us that the prolonged action of the 
natural agricultural solvent (carbonic acid water,) is capable of effecting 
decompositions which, in a shorter period of time, the strongest mineral 
acids are unable to bring about. 
More precise information than any we yet possess on the subject of 
green manuring is desirable ; in this section at least it would be interest¬ 
ing and useful to know whether clover generally succeeds in the soils and 
climate of this State ? What has been found to be the best mode of se¬ 
curing a full plant ? What is the effect of plaster on the growth of clover 
in different soils, and in what stage of the plant’s growth, or under what 
circumstances, does it exercise the greatest influence ? What is the rela¬ 
tive cost of clover as compared with green rye, buckwheat, &c., and 
what are the effects of such on the following crop ? Is there any green 
crop which may be profitably substituted for clover? I have been led 
to dwell at greater length on the subject of manures than I at first in¬ 
tended, or than is required in a brief essay like this, intended chiefly to 
illustrate some of the more important points of the physiology of plants. 
But situated as we are so far from the sea board, and having as yet few 
large towns or manufactories in our midst, affording cheap extraneous 
supplies of manure, I am strongly convinced of the paramount import¬ 
ance of economizing and increasing the quantity which may be made on 
a farm. The great attention paid to improving and enriching the soil is 
the main cause of the rapid improvement of farming in Britain of late 
years. The chief object of the extensive culture of the rutabaga and 
