464 AGRICULTURAL ENGINEERING 



moisture to leave. The wall must be strong and rigid enough 

 to resist the bursting pressure of the silage, and sufficiently 

 smooth on the inside to permit the silage to settle readily. 

 In addition to these absolute essentials, there are many 

 features which add to the value of a silo and which should 

 be considered in its selection. Some of these features are 

 as follows: 



1. It is highly desirable that a silo be as durable and 

 permanent as possible. All parts should be constructed 

 of materials which will insure a long term of service. 



2. The silo should require a minimum expenditure of 

 labor and materials for maintenance. This refers to the 

 adjustment of parts for shrinkage and expansion, repainting, 

 and the substitution of new parts for those which have 

 become decayed or otherwise useless. 



3. The silo should have a wall which will prevent as far 

 as possible the freezing of silage. 



4. The silo should be arranged in such a manner as to 

 be convenient for filling and for the removal of the silage. 

 This refers directly to the construction of the doors. 



5. In some cases it is desirable to have a silo which may 

 be taken down and moved from one location to another. 



6. A fire-proof silo may have the further advantage of 

 serving as a fire wall. 



7. A silo should be sightly and should add to the appear- 

 ance of the farmstead. 



8. It is an advantage to have a silo of simple construc- 

 tion, which may be erected with the minimum of skilled 

 labor, and in the construction of which there is little chance 

 for expensive mistakes. 



9. Lastly, the silo of the lowest cost per unit of capacity, 

 giving due consideration to the other features of merit, is the 

 most desirable, 



