24 Practical Farming 



individually, a film of water. Still, the fineness of the 

 clay soil makes it far more retentive of moisture than a 

 coarse or even a fine sand. The computations of Professor 

 King are meant to be comparative and not actual to a 

 further extent than he has computed. 



The texture of the soil has a great deal to 



Varieties of ^^ ^-^j^ ^^^ ^ -^^ which the rain water, 



Soil Texture , , . , , ^ , . . , «. ^ ., a 



laden with the carbonic acid, affects it. A 



piece of rock may lie on the surface for ages and suffer 

 very Uttle loss in bulk. But if the same rock is pulverized 

 into an impalpable powder and mixed with the soil, its 

 decomposition will be comparatively rapid. This is well 

 illustrated by the case of the phosphatic rock dredged 

 from the rivers of South Carolina, where it has lain for 

 countless centuries slowly wearing and being rounded. 

 But when put into a mill and reduced to the impalpable 

 powder sold on the market under the name of "Floats," 

 it becomes a useful plant food which is readily acted 

 upon by the rains and the combinations of matter in the 

 soil. 



Pelouze, a French chemist, found that a flask in which 

 water was kept boiling for five days lost less than two 

 grains in weight; but when he broke off the neck of the 

 flask, reduced it to a fine powder, and boiled it five days, 

 he found that one-third of the weight of the flask had been 

 dissolved by the water. If, then, such an insoluble ma- 

 terial as glass can be thus dissolved by the action of hot 

 water, we can begin to realize what is going on in the soil 

 in which the action of the sun's rays has set up heat, and 

 in which the fineness of the soil gives the rain water an 

 opportunity to act. 



