Concrete Silos 47 



inforced, is a permanent structure. There are no hoops 

 to tighten, no danger from blowing down or from fire. 

 It grows stronger and more stable with each succeeding 

 season. It is good for generation after generation. In 

 some places, owing to cost of material, the initial cost 

 may be a little more than the cost of a wood stave silo, 

 but in the end it is a more economic structure. " 



With reference to the metal silo, it will scarcely be 

 necessary to do more than quote a paragraph from the 

 catalogue of one of the companies selling these silos. 

 It states: 



"In the production of silage, certain mild acids are 

 formed by fermentation, which, if no protection were 

 afforded, would have a tendency to cause the galvan- 

 izing to corrode. To provide against this it is advisable 

 to keep the inside of the silo painted with some elastic, 

 acid-resisting paint." 



In another paragraph the company advises its cus- 

 tomers to paint the inside of the silo once a year; and 

 this, too, is a company which is selling silos of "pure 

 iron" the kind which is supposed to be proof against 

 attacks of any kind. 



Granting that the acid in silage does have a slight 

 effect upon concrete, such a wall, with a thickness of 

 several inches, will certainly be more durable than a 

 metal wall having a thickness of a small fraction of an 

 inch. 



The table on the following page, which is a com- 

 pilation of 296 replies to inquiries sent out to Missouri 

 farmers, will serve to show the difficulties experienced 

 with silos of various kinds and the kind of silo pre- 

 ferred, if another should be built. 



