USES OF STONE IN THE SOIL. 131 



longer the sun's heat is retained after night fall, or after a 

 change in the weather. The exemption from feosts of light 

 sandy lands while peaty soils are more subject to them is 

 another result of this quality. 



The state of division of the particles of a soil is intimately 

 connected with its density and weight. The exceedingly 

 fine particles of which the "loess" soils of Nebraska and of 

 the Mississippi bottoms consist, and the coarser nature of 

 the gravelly lands of New England, certainly have much to 

 do with their productive character and money value, because 

 these are controlled by ease of working and facility of man- 

 agement, quite as much as by their fertility ; and this prop- 

 erty is not to be lightly passed over or ignored, in this con- 

 sideration. Sonie considerable quantity of stone is not 

 considered by many farmers as injurious or even objection- 

 able; for when the stone is not large enough to interfere 

 with the employment of the implements, the plow, harrow, 

 drill, and mower and reaper, it is really a benefit, for it 

 warms the land in the winter and cools it in the summer, 

 condensing moisture around it in the latter case and so aid- 

 ing considerably in the growth of the crops. The frag- 

 ments of certain kinds of rocks, especially the fossiliferous 

 slates and limestones, are quickly worn dow r n by the weath- 

 er and contribute to a useful extent to the mineral plant 

 focd of the soil ; so that there are cases in which a moderate 

 quantity of loose stone in the soil is a benefit rather than 

 an incumbrance, in more ways than one. This is the case in 

 western New York where the fossiliferous limestone prevails 

 and in eastern Pennsylvania and southward along the moun- 

 tains, where the micaceous schists and slates and the mag- 

 nesian talcose rocks abound ; and in their gradual wearing 

 down furnish new supplies of plant food to the land. 



When soils cohere and become hard and cloddy, or, bake 

 into a hard crust on the surface after rain, this is objection- 

 able ; as compelling the farmer to spend a good deal of la- 

 bor in reducing the clods and pulverizing the surface by 

 frequent cultivation. Sandy loams and light clay loams 

 have not this objectionable coherence ; while stiff clays are 



