28O SOILING CROPS AND THE SILO. 



building them therefore will be discussed at some 

 length. (See Page 317.) 



Wood silOvS are such as are constructed wholly 

 of wood, but usually resting on a foundation of 

 stone or concrete. Because of the relative cheap- 

 ness of construction in the past, there is an over- 

 whelming preponderance in the number of the silos 

 that have been built of wood. The kinds of wood 

 chiefly used in their construction have been pine in 

 certain of its species, as the white and yellow, the 

 southern cypress and the Douglas fir. But any kind 

 of wood will answer that is durable, cheap and that 

 does not warp. The spruce of the Puget Sound 

 country would probably prove very suitable and 

 possibly the hemlock also. The chief objection to 

 wood silos is their want of durability. In the not 

 distant future they must also become more costly 

 with the increasing dearness of lumber, and as they 

 do stone silos will grow in favor. The construction 

 of certain forms of the wood silo will be discussed 

 at some length. 



Foundation for Silos. Whatever the form of 

 silo built, it ought to rest on a foundation that is not 

 subject to decay. The foundation therefore should 

 not be of wood. Stone will be the material most 

 commonly used, though there may be some instances 

 in which bricks would be even less costly. Usually 

 the foundation is sunk beneath the line of frost, but 

 this is not always necessary. In soils which hold 

 much water, every care should be taken to carry it 

 away, as fast as it accumulates, by tiles laid for the 

 purpose. When silos are sunk into the ground, it 

 is not necessary to have the foundation go down 



