: 
. 
— 
Agriculture and Chemistry. 295 
Agricultural chemistry, so called, has explained, or at- 
tempted to explain, effects long before observed, and familiar 
in the practice of good farmers; but it has not taught the 
farmer to till his land better and more cheaply, to drain it 
better, or to clean it better: it has not added one plant to 
those before cultivated, nor taught the farmer to cultivate 
one crop better than he could do before. It has not taught 
him to employ one mechanical machine more usefully ; nor 
taught the mechanics who construct these machines to 
adapt them better to the uses of the farmer. It has not 
added one manure to the list half so important as those before 
known, such as lime, marl, gypsum, bones, rape-dust, soot, 
ashes, the refuse of towns and manufactories, guano, and it may 
be said, any one of the animal and vegetable substances which 
had been before familiar. These were all in use, and the times 
and modes of applying them had been determined by farmers 
themselves, before agricultural chemistry was heard of. Or 
if we allow that some additional compounds have been added 
to the former ample list of such substances, no one surely 
will say that this has affected in a sensible degree the condi- 
tion and prospects of the farmers of this country. Even the 
use of the alkaline salts, of which so much has been said, was 
known to the degree in which it was thought beneficial to em- 
ploy them. Saltpetre, which may be regarded as the type of 
the class—the type, I mean, as regards its effects upon the soil 
—has been used by the farmers of England for more than a 
hundred years, either by itself, or in the refuse matter of 
gunpowder works. They had learned that, though a power- 
ful stimulant, it did not add that permanent fertility to the 
soil which it is the great end of good farming to communicate. 
A similar substance, nitrate of soda, which can be obtained 
in unlimited quantity from a vast deposit of it in South Ame- 
rica, and which can be imported at a cheap rate, was em- 
ployed by farmers several years ago, in large quantities ; but 
‘the use of it has now almost ceased, which could not have 
happened had the employment of it been found very advan- 
tageous. But if, in the matter of manures, which, of all others 
useful to the farmer, is the subject which chemistry is best 
fitted to investigate, more has not been done than we know 
