432 TRANSACTIONS OF THE 



diiferenee can be obviated artificially by drainage, so as to leave 

 less water to cool the air by evaporation. Thus you save heat, 

 as much being required for the vaporisation of water, as would 

 elevate' the temperature more than three and a quarter million 

 times its bulk of air one degree. 



It is therefore true that every inch of water carried off by 

 drains, which would otherwise evaporate, as much heat is pre- 

 served per acre as would elevate twelve thousand million cubic 

 feet of air a single degree in temperature; showing how much 

 the want of drainage renders the air cold, and liable to the for- 

 mation of dew and fogs. You can readily understand then how 

 local climate is affected by surplus water in the soil, and the 

 reason why it is so vastly improved by drainage. 



I asked a farmer ivho resided near a twenty-six acre tract of 

 land that I drained in Ulster county, what the effect had been on 

 the temperature, he replied " that all he knew about it was that 

 before I drained it he could not go out at night without an over- 

 coat, and that now he could with perfect impunity, on account of 

 his improved state of health; that before the drainage some 

 member of his family was always in the hands of a physician, and 

 that now a dootor was never required.'' I am perfectly con- 

 vinced in my own mind that in consequence of this improve- 

 ment I have raised the temperature of the whole district one 

 degree, the evaporation being greatest in summer, the rise of 

 temperature is of course the greatest at that season. Experi- 

 ment last summer with the thermometer showed me a difference 

 of nearly seven degrees between the piece of land in question and 

 a neighboring swamp, and there was a corresponding difference in 

 the temperature and dampness of the atmosphere. Therefore, 

 farmers, you may make a climate for yourselves, genial by drain- 

 ing or otherwise by neglect. How can you employ your capital 

 more satisfactorily 1 The following are the principal agricultural 

 adv^antages of drainage: 



1. By removing that excess of moisture which prevents the 

 permeation of the soil by air, and obstructs the free assimilation 

 of nourishing matter by the plants. 



2. By facilitating the absorption of manure by the soil, and so 

 diminishing its loss by surface evaporation, and by being wasted 

 away by heavy rains. 



3. By preventing the lowering of the temperature and the chil- 

 ling of vegetation, diminishing the effect of solar warmth not on 

 the surface merely, but at the depth occupied by the roots of 

 plants. 



