THE VARIOUS TYPES OF SILOS. 59 



nailed to uprights, or or single planks (staves), or may be 

 plastered inside. The material used will largely be de- 

 termined by local conditions; where lumber is cheap, and 

 stone high, wooden silos will generally be built; where the 

 opposite is true, stone or brick silos will have the advan- 

 tage in point of cheapness, while concrete silos are likely 

 to be preferred where great permanency is desired or 

 where cobble-stones are at hand in abundance, and lumber 

 or stone are hard to get at a reasonable cost. So far as 

 the quality of the silage made in any of these kinds 0!f 

 silos is concerned, there is no difference when the silos 

 are properly built. The longevity of stone and concrete 

 silos is usually greater than that of wooden silos, since 

 the latter are more easily attacked by the silage juices 

 and are apt to decay in places after a number of years, 

 unless special precautions are taken to preserve them. A 

 well-built and well-cared-for wooden silo should, however, 

 last almost indefinitely. 



As regards the form of the silo, it may be built in 

 rectangular form, square, octagon or round. We have 

 already seen that the most economical of these is ordi- 

 narily the round form, both because in such silos there is 

 less wall space per cubic unit of capacity, and in case of 

 wooden round silos, lighter material can be used in their 

 construction. The only place where silos of square or 

 rectangular form are built now is inside of barns, 

 where they fit in better than a round structure. We shall 

 later on give directions for building silos inside of a barn, 

 but shall now go over to a discussion of the various forms 

 of round silos that are apt to be met with. More round 

 wooden silos have been built during late years in this 

 country than of all other kinds of silos combined, and this 

 type of silo, either built of uprights lined inside and out- 

 side with two layers of half-inch boards, or of one thick- 

 ness of staves, will doubtless be the main silo type of the 

 future; hence we shall give full information as to their 

 building, and shall then briefly speak of the other forms 

 mentioned which may be considered preferable In ex- 

 ceptional cases. 



