238 



STATE BOARD OF AGRICULTURE. 



The doorway, which is continuous as in the other, is kept from 

 spreading by % inch round bolts set 3G inches apart. 



The inner wall is composed of two layers % inch by 3^/2 inch south- 

 ern pine, with a layer of tar paper between, but put on in the same 

 manner as was the basswood sheeting in the other silo. After ten 

 years this sheeting seems to be in a perfect state of preservation. 



The roof differs in its construction from the other merely in having 



Fig. 26. All wood silo, built in 1897. 



the rafters set 18 inches apart, center to center, on the plates instead of 

 24 inches apart. 



Ventilation between the walls is secured by means of 1 inch auger 

 holes bored from the outside into each of the spaces between the studs 

 at the bottom, and from t'>e inside of the silo into these spaces at 

 the top. While this does not provide for the freedom of air movement 

 required by Prof. King and other authorities on silo construction, it 

 is helpful in preserving the walls of the silo. 



The cement silo. Fig. 27, is of the solid wall type. It has an inside 

 diameter of 15 feet and a height of 31 feet, standing about 5 feet in 



