236 AGRICULTURR OF MAINE. 



KOUNDATION WALL. 



If the silo is to be made of concrete, the foundation wall 

 may be the same thickness as the walls of the silo ; that is. 6 in. 

 to 8 in. If not a concrete superstructure, 6 in. to 12 in. will be 

 sufficient for the walls. If this wall comes above the surface 

 of the ground (it usually does), reinforcement must be pro- 

 vided. This reinforcement may be of wire or iron rods, de- 

 pending- upon the size of the silo. These data may be obtained 

 from the cement companies or dealers when purchasing cement 

 for the foundation. If a concrete or stone silo is to be built, 

 vertical reinforcement rods should be placed in the foundation ; 

 if a stave silo is being built, eye bolts should be placed in the 

 concrete so that the silo may be anchored. 



The foundation may be made of other material than con- 

 crete, such as stone, brick, hollow tile filled with concrete, or 

 concrete blocks. These are used according to conditions. 



STAVE SILO. 



Any substantial weather-resisting lumber can be made into 

 a good silo. The following woods are used for staves : Cy- 

 press, white pine, cedar, redwood, tamarack, long leaf southern 

 pine, spruce, and sometimes even hemlock. The Bureau of 

 Forrestry, U. S. Department of Agriculture, makes the follow- 

 ing statement regarding the average number of years wood 

 will remain without decay (Mo. A. E. S. R. 103) : 



TABLE VI. 



Species Ave. No. Yrs. Life Untreated 



Cypress 14 



Redwood '. 14 



Douglas fir 10 



Yellow pine 8 



White pine 8 



Dipping in or painting with a preservative is recommended 

 and many silo companies furnish such preservatives or treat 

 the lumber by dipping before it is shipped. Coal tar preserva- 

 tives can usually be purchased from dealers in any of the 

 larger towns. 



