[ 5 3 



the constitution of the soil, which may be easily dis- 

 covered 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 ascertaining the 

 cause, or of removing the effect. The application of 

 chemical tests in such cases is obvious ; for the soil 

 must contain some noxious principle which may be 

 easily discovered, and probably 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 

 thei'e 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 lime- 

 stone to be employed in cultivation often occurs. 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 ; and the fitness of its 

 application, whether as a manure for different soils, or 

 as a cement, determined. 



Peat earth of a certain consistence and composi- 

 tion is an excellent manure j but there are some varie- 

 ties of peats which contain so large a quantity of fer- 

 ruginous matter as to be absolutely poisonous to plants. 



