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well-tilled soil. The ancient Romans recognized 

 this principle fully, for, as we have already seen, 

 Cato says that the first commandment of Agricul- 

 ture is to plough ; the second, to plough again ; 

 and the third, to plough a third time. 



But, as a matter of course, no degree of ploughing 

 will avail the practical agriculturist if his land is 

 deficient in any of the substances constituting 

 plant-food, in which case such deficiency must be 

 supplied, whether it be potash or soda, lime or 

 magnesia, silica or phosphoric acid ; and, to ascer- 

 tain the element that is so wanting, the agriculturist 

 should seek the aid of the chemical analyzer. 



Drainage is another mechanical improvement of 

 the soil adapted for dry crops. It removes from 

 the subsoil all the stagnant water that is so 

 injurious to our edible crops ; it causes the atmos- 

 pheric air to penetrate deeper through the pores of 

 the soil ; and, following the air, the roots penetrate 

 into the lower strata of the soil, and furnish addi- 

 tional nourishment to the plant from a fresh and 

 abundant source. 



But although these mechanical operations are 

 most important, and will effect marvellous improve- 

 ments in neglected soils, the action of chemicals in 

 effecting a decomposition of the chemically com- 

 bined food elements, and distributing them in the 

 soil, is still more powerful. The addition of lime, 

 for instance, has a most wonderful effect on all 



