5 
If* land be unproductive, and a system of ame T 
liorating it is to be attempted, the sure method of* 
obtaining the object is by determining the cause 
of its sterility, which must necessarily depend 
upon some defect in the constitution of the soil, 
which may be easily discovered by chemical 
analysis. 
Some lands of good apparent texture are yet 
sterile in a high degree ; and common observation 
and common practice afford no means of ascertain- 
ing the cause, or of removing the effect. The 
application of chemical tests in such cases is ob- 
vious ; for the soil must contain some noxious 
principle, which may be easily discovered, and pro- 
bably easily destroyed. 
Are any of the salts of iron present? they may 
be decomposed by lime. Is there an excess of 
siliceous sand ? the system of improvement must 
depend on the application of clay and calcareous 
matter. Is there a defect of calcareous matter ? 
the remedy is obvious. Is an excess of vegetable 
matter indicated ? it may be removed by liming, 
paring, and burning. Is there a deficiency of 
vegetable matter ? it is to be supplied by manure. 
A question concerning the different kinds of 
limestone to be employed in cultivation often oc- 
curs. To determine this fully in the common 
way of experience, would demand a considerable 
time, perhaps some years, and trials which might 
be injurious to crops ; but by simple chemical 
tests the nature of a limestone is discovered 
in a few minutes - P and the fitness of its appli- 
b 3 
