STONE AND CEMENT CONSTRUCTION. 491 



SOLUTION. 



12X36X3=1296. 



129616-81 tons. 



This silo being 6 feet over 30 feet in depth; take 6 per 



cent of 81 tons which is 4.86. 

 81+4.86=85.86 tons total weight or capacity of silo. 



It has been determined that the pressure of ensilage against 

 a silo will increase with the depth and is equal to n pounds per 

 square foot of each foot of depth. Thus at a depth of 20 feet 

 the bursting pressure is 220 pounds per square foot, and at a 

 depth of 30 feet it is 330, and at a depth of 40 feet it is 440 

 pounds. 



By referring to the table on page 531 the tensile power 

 of wire, or wood may be found and from this it is possible to de- 

 termine the size of wires, rods or hoops that are necessary to 

 hold together the walls of a silo, that is to be filled with ensilage. 



NOTE. Where the material is cut fine and the silo is filled slowly, 

 the amount that can be put into a silo will be greater. 



Important Facts About the Silo. 



The value of the silo for the preservation of green material 

 for feeding stock has been thoroughly tested in nearly every 

 state and has demonstrated some of the following well estab- 

 lished facts : 



1. It prevents loss and waste of feed. 



2. It is an economic way of handling food. 



3. Silage is more palatable than fodder. 



4. The same amount of corn in the silo will produce more milk 

 than if fed as fodder and ears. 



5. The principle used in the silo is the same as that used in canning 

 fruit. 



6. When silage is packed in the silo, it becomes heated and the 

 air in the feed is changed to carbon dioxide. 



7. When the air is exhausted the silage will stop decaying. 



8. Silage will keep indefinitely if no air can get into it. 



9. Silos have been built of stone, cement, brick, lumber and steel. 



10. Some of the cheapest silos have been constructed of lumber. 



11. It is not advisable to build a silo more than 16 feet in diameter, 

 except for feeding large herds. 



12. A layer of silage at least 2 inches in depth should be removed 

 each day. 



