THIRTY-FIFTH ANNUAL CONVENTION. 277 



in a fair state of preservation outside. A northern pine silo 

 four years old, was found in poor condition with the lower 

 ends of the staves badly rotted even though placed on a good 

 high foundation. 



In caring for a silo, care should be taken to keep it well 

 painted outside. Most manufacturers advise that white lead 

 be placed in the joints when the silo is erected and that the in- 

 side of the staves be painted with some form of wood preserva- 

 tive. 



All stave silos outside of barns, even when secured by guy 

 wires, are more or less at the mercy of the wind and weather. 

 If there are any imperfections in the lumber they are quite like- 

 ly to develop, and if there is any tendency on the part of the 

 staves to warp they will be sprung out of shape. This is per- 

 fectly true of silos with tongued and grooved staves and deplor- 

 ably true of silos with plain staves. 



Selecting Lumber for the Stave Silo. 



In the purchase of a stave silo, the selection of the kind and 

 grade of lumber is of the greatest importance. It is stated in 

 the catalogue of one of the leading manufacturers selling silos 

 in Iowa that "the quality of the lumber used really determines 

 the success or failure of the silo." Badly cross-grained lum- 

 ber or any containing heart or wind shake, sap ,or bark should 

 be discarded. In order to have an opportunity to sort the 

 lumber the silo should be ordered early and an early delivery 

 guaranteed so that all poor staves may be discarded and new 

 ones secured to replace them even if it is entirely at the pur- 

 chaser's expense. A poor stave should never be put in a silo, 

 as it lowers the value of the entire structure. This is true of 

 all kinds of lumber and the judging of its quality must rest 

 with the purchaser. There are, however, some qualities and 

 characteristics which are of importance in silo construction 

 that are possessed to a different degree by different woods used 

 in silo construction. Following is a discussion of the different 

 woods commonly used in silo construction named in order of 



