19-i CULTIVATION. 



the soil by freezing, as it always does, from the up- 

 right position taken by the particles of ice. 



12. We are enabled to work sooner after rains, 

 because the water descends, and is immediately re- 

 moved, instead of lying to be taken off by the slow pro- 

 cess of evaporation, and sinking through a heavy soil. 



13. The effects of cold weather are kept off longer 

 in the fall, by the removal of the excess of water 

 which would produce an unfertile condition on the 

 first appearance of cold weather. 



The drains also, from causes already named (3), 

 keep the soil warmer than before being drained, thus 

 actually lengthening the season, by making the soil 

 warm enough for vegetable growth earlier in spring, 

 and later in autumn. 



14. Lands are prevented from becoming sour by 

 the formation of acetic acid, etc., because these acids 

 are produced in the soil only when organic matter 

 decomposes in contact with an excessive quantity of 

 water. If the water is removed, the decomposition 

 of the organic matter assumes a healthy form, while 

 the acids already produced are neutralized by atmos- 

 pheric influences, and the soil is restored to a condi- 

 tion in which it is fitted for the growth of the more 

 valuable plants. 



15. The decay of roots, etc., is allowed to proceed, 

 because the preservative influence of too much water 

 is removed. Wood, leaves, or other vegetable matter 

 kept continually under water, will last for ages ; 

 while, if exposed to the action of the weather, as in 

 under-drained soils, they soon decay. 



