CONSroERATIONS REGARDING MLXCHIXG. 35 



eolation ; the remainder was drawn to the surface and evaporated 

 by the process described ; or contributed to the support of vegeta- 

 tion. The natural tendency of earth3' matter thus to raise water is 

 not generall}' appreciated, but can be readily seen when so dry and 

 porous a material as coal-ashes is deposited upon a slightly 

 damp surface. Although the heap be quite large, yet, in a short 

 time, I have observed the dampness to have penetrated through 

 the entire mass from below. Anything that breaks up the uniform 

 continuity of the texture of the soil, by which atom after atom of 

 water is brought to the surface, will accomplish the first step in 

 retaining the moisture of the soil, under conditions favorable to 

 vegetation. 



Now mulching does not do this at all. It onl}' checks or mod- 

 erates the approach of the atmosphere to the moistened surface of 

 the soil, and therefore retards evaporation to that extent ; but the 

 reason why there is alwa^'s so much moisture beneath the mulch is 

 because the capillary action of the soil elevates the water to the 

 surface faster than it can evaporate. 



Any material of loose texture that is a good non-conductor of 

 heat will, when applied to the surface of the ground, retard the 

 movement of the air and prevent evaporation. 



Spent tan bark meets this requirement better than any other ma- 

 terial that can be applied to the laud. It is light and porous, and 

 therefore retains a cushion of confined air, which is one of the 

 best non-conductors in nature. The gentle showers, which simply 

 moisten the earth, pass through it readily, as do the heavier rains, 

 which are absorbed and longer retained. 



Now dr^' soil is likewise an excellent non-conductor, made 

 doubly such by being loosened and pulverized, and thus intermin- 

 gled with air. This is preciselj- the condition of the soil after a 

 thorough cultivation ; when thus rendered fine and light the sur- 

 face becomes trulj' a cushion of air and dry earth, the continuity of 

 the insensible process of convection of the water of the soil is 

 broken, the point at which the upward passage of the water of the 

 soil ceases is removed to the depth of the cultivation, the free ac- 

 cess of the air to the continuously moist surface is hindered, and 

 3'ou have accomplished all of the beneficial effects of mulching in 

 a cheaper, more intelligent, and scientific manner. 



Years of observation and considerable experience have indicated 

 clearl}- that the best mulching is the hoe, or the rake and cultivator. 



Many an observant farmer has borne his testimony to the sue- 



