42 EARTHS AND SOILS. 



cal Report, "is to secure a sufficient degree of fineness, 

 that they may be incorporated with the soil, and form, 

 strictly speaking, a constituent part of it. To attain this 

 object, it is necessary that they should be raised in the 

 autumn, and placed in heaps, that they may be exposed 

 to frosts and the atmosphere through the winter. To 

 assist still further in the process of pulverization, it is bet- 

 ter to mix them with barn-yard materials, straw, manure, 

 and refuse of any kind, either animal or vegetable. This 

 course being pursued with them, they should be spread 

 as evenly as possible upon green sward, that they may 

 enjoy the further benefits of air, moisture, &c., by direct 

 exposure during the season. Besides, the grass, passing 

 up through the layer, will assist greatly in producing a 

 comminuted state. The succeeding season it is in a state 

 to be ploughed in, when it is duly prepared to become a 

 constituent part of the soil. It is only in this way that 

 the stiff and adhesive clays can be broken up, and pre- 

 pared for, and incorporated with, the other earths." 



Our practice differs somewhat from the preceding rec- 

 ommendation of Professor Emmons. Our leisure time 

 for drawing clay is generally in the winter, and we are 

 enabled to obtain it at this season from the clay-banks in 

 Albany. We do not place it in piles, or mix it with other 

 materials ; but scatter it immediately from the wagon upon 

 the sward, as evenly as its adhesive properties will per- 

 mit. In this way it becomes better exposed to the ame- 

 liorating influence of the weather. The frosts and the 

 rains break down the lumps ; and when the clay has after- 

 wards become dried, it is readily pulverized with the maul 

 or roller, and distributed by the harrow. 



Upon the utility of employing vegetable or animal sub- 

 stances, in conjunction with marl, or other varieties of 

 calcareous manure. Professor Emmons remarks : — 



" It must be plain that carbonate of lime, or sulphate 

 of lime, cannot support vegetation without other materials. 

 It appears, however, that a large proportion of the food 

 of plants exists in the earth in an insoluble state ; that it 

 is by a chemical union of this calcareous matter and this 

 insoluble vegetable substance, that it becomes soluble, 



