316 SOILING CROPS AND THE SILO. 



They may also be of the same size as those described 

 in the stave silo, where the distance between the studs 

 will admit of making them thus, and they may be 

 similarly distanced. They may likewise be beveled 

 on the edges and held together by bars bolted to the 

 outer edge of the wall before the doors are cut out. 

 A simpler form of door has been made by cutting 

 out an opening of sufficient size between two studs 

 and holding together the part of the lining thus cut 

 out by bars nailed or bolted to them on the outside. 

 When in place they rest against strips nailed to the 

 two sides of the two studs adjacent to the opening 

 for the door*. When the doors are in place they are 

 covered with tarred paper to aid in excluding the 

 air. Where an outer lining has been put on, open- 

 ings to correspond with those of the inner lining may 

 be made on the same general plan. 



The Roof. It is only when the rectangular silo 

 extends up through the roof of the outbuilding, or 

 when the silo is built outside that it requires to be 

 roofed. The plates which are spiked onto the top 

 of the studs, or which have the latter mortised into 

 them, should be less wide than the studs that venti- 

 lation may be provided for the air space between the 

 inner and outer linings of the wall. Plates are fre- 

 quently used no thicker than the studs, but in silos 

 possessed of much width it would be no more than 

 prudent to use plates somewhat thicker. The size 

 of the rafters used should be regulated by the size 

 of the silo. When in position they are notched 

 where they rest on the plates and are spiked and toe- 

 nailed to the same. If narrow boards or 2x4 scant- 

 lings are nailed or spiked to opposite rafters and not 



