ON THE FORM OP SILOS. 55 



the mass was weighted at the rate of one hundred pounds 

 per square foot. 



It was found, however, after some time, that this 

 heavy weighing could be dispensed with by making the 

 silos deep, and gradually the deep silos came more and 

 more into use. These silos were first built in this country 

 iii the latter part of the eighties; at the present time 

 none but silos at least twenty to twenty-four feet deep are 

 built, no matter of what form or material they are made, 

 and most silos built are at least twenty-four to thirty 

 feet deep, or more. 



Since 1892 the cylindrical form of silos has become 

 more and more general. These silos have the advantage 

 over all other kinds in point of cost and convenience, as 

 well as quality of the silage obtained. We shall, later 

 on, have an occasion to refer to the relative cost of the 

 various forms of silos, and shall here only mention a few 

 points in favor of the round silos. 



1. Round silos can be built cheaper than square 

 ones, because it takes less lumber per cubic foot capacity, 

 and because lighter material may be used in their con- 

 struction. The sills and studdings here do no work ex- 

 cept to support the roof, since the lining acts as a hoop 

 to prevent spreading of the walls. 



2. One of the essentials in silo building is that there 

 shall be a minimum of surface and wall exposure of the 

 silage, as both the cost and the danger from losses 

 through spoiling are thereby reduced. The round silos 

 are superior to all other forms in regard to this point, 

 as will be readily seen from an example: A rectangular 

 silo, 16x32x24 feet, has the same number of square feet 

 of wall surface as a square silo, 24x24 feet, and of the 

 same depth, or as a circular silo 30 feet in diameter and 

 of the same depth; but these silos will hold about the 

 following quantities of silage: Rectangular silo, 246 tons; 

 square silo, 276 tons; circular silo, 338 tons. Less lum- 

 ber will, therefore, be needed to hold a certain quantity 

 of silage in case of square silos than in case of rectangular 



