CHEMISTRY OF AGRICULTURE. 405 



politic, be so exerted, that the rising generation, at least, may- 

 receive the requisite instruction, and that tlie farmers who are 

 to come after us, may afflict the soil less, and profit more by 

 its acquaintance. 



What plants are made of, is the first point on which the 

 farmer is to inform himself; but before he is qualified for 

 practical work he must understand the reason why he drains, 

 why he ploughs, and why he hoes. If these operations are 

 necessary, they are necessary for good and sufficient reasons, a 

 comprehension of which is not only indispensable to the true 

 farmer, but is easily acquired. For instance, let us see why 

 and how draining is beneficial. 



Good and efficient underdraining accomplishes, among others, 

 the following results : — 



1. It entirely overcomes drought. 



2. It furnishes an increased supply of atmospheric fertilizers. 



3. It warms the lower portions of the soil. 



4. It hastens the decomposition of roots and other organic 

 matter. 



5. It accelerates the disintegration of the minerals in the 

 soil. 



6. It causes a more even distribution of nutritious matters 

 among those parts of the soil which are traversed by roots. 



7. It improves the mechanical texture of the soil. 



8. It causes the excrementitious matter of plants to be car- 

 ried out of the reach of their roots. 



9. It prevents grasses from running out. 



10. It enables to deepen the surface soil. 

 By removing excess of water : — 



11. It renders soils earlier in spring. 



12. It prevents the throwing out of grain in winter. 



13. It allows us to work sooner after rains. 



14. It keeps off the effects of cold weather longer in the fall. 



15. It prevents the- growth of acetic and other organic acids, 

 which induce the growth of sorrel and similar weeds. 



16. It hastens the decay of vegetable matter and the finer 

 comminution of the earthy parts of the soil. 



17. It prevents in a great measure the evaporation of water 

 and the consequent abstraction of heat from the soil. 



18. It admits fresh quantities of water from rains, etc., 



