Till; DKAIXAGE OF THE FARM. 457 



a satisfactory manner, without feeling that great and permanent evil was 

 being done to it ? That water does not stagnate in the soil without mak- 

 ing it poorer and more unproductive than it would be were it lying in a 

 dry state. Then, as the farmer is often compelled, by the advance of the 

 season, to work his undrained land before it is nearly dry enough, the 

 pressure from the feet of the horses bakes it, and greatly reduces its per- 

 meability. 



The soil, in this way, is injured mechanically as well as chemically, for 

 stagnant water does a two-fold injury. Chemists tell us, that evapora- 

 tion is productive of cold. Now, if a very large quantity of water is to 

 be evaporated from the soil by the sun's rays, the temperature of the sur- 

 face stratum will necessarily be considerably lowered. It takes as much 

 heat to evaporate a cubic inch of water as would raise the temperature of 

 5 inches from the freezing to the boiling point. To evaporate an inch of 

 rainfall from an acre of land, requires an amount of heat from the sun, 

 which would be sufficient to raise the temperature of the dry soil of a 

 whole acre, to the depth of 10 inches, no less than 99 degrees. When we 

 consider that upwards of 25 inches of rain-fall are evaporated in many 

 parts during a year, the enormous importance of under-drainage, as a 

 means of preventing the temperature of the soil from being lowered, can- 

 not fail to be observed. A wet soil, which must become dry in spring 

 mainly by a process of evaporation, will always be cold ; and the crops 

 grown upon it will be later than if it were freed from its stagnant water 

 i of under-drainage. Even the temperature of a district is 

 considerably lowered by there being much evaporation from the soil. 

 II. nee the liability to injury from frosts, of those crops in late districts, 

 that are grown in the vicinity of marshy land. 



11 known, also, that while stagnant wut<-r is a bad conductor 



dow of the heat which its surface receives from the sun's rays, it 



imunicatea cold to the soil lying underneath. Tin: ^ivater 



part of the heat which is ab.v.rl-,l by ,-. badly drained soil is radiated into 



, tin- nijjit.-tiim- ; whereas in dry, well wrought land, much of it 



1 up at a invater or Irss depth, and become-, useful afterwards in 



.Kilat'mi: H tb of th.- prudur... \Vli--n t!. r in 



-oil, th development of acids, and compound lous 



kinds, inimieal to tie- health of the crops grown upon it. A- new rain 



fall with the old water, a unit ua! decompo- -it i. >n an-i 



conversion < .1 pound substances pi -latural o.n sequence J 



but air injuriu> to vegetable life, in a cliemieal sense, 



win T is also hurtful to the land both chemically and : 



