THE SILO. 405 



o«e of reasonable size. Many farmers prefer to have two silos. They 

 feed from one during the winter, and have tlie contents of the other 

 for mid-summer's feeding." 



CONSTRUCTION OF SILOS. 



Essential Features.— It does not matter what material the silo is 

 made of; it must be air tight on sides and at bottom. Any crack or 

 knot hole or poor joint at the door will admit air, and the silage will 

 rot just in proportion to the amount of air that enters. The receptacle 

 must be strong enough to withstand the lateral pressure of the silage 

 when it settles. This lateral pressure at 10 feet from the top is no 

 pounds per square foot, at 20 feet 220 pounds, and at 30 feet, 330 

 pounds, .and at 40 feet, 440 pounds. It is very difficult to make deep 

 rectangular silos whose walls will not spring enough to allow air to 

 circulate up and down the sides and cause losses. 



Depth of the Silo. — This should be made as great as practical, 

 because, ist, in this way the largest amount of food per cubic foot of 

 space may be stored; and, 2nd, the silage keeps better because packed 

 so solid; and, 3rd, there is less relative loss at the surface. The top 

 of the silage always spoils to a depth of 2 to 8 inches. No silo should 

 be less than 25 feet deep. A silo 20x40 will hold twice as much as one 

 20x25, and one 36 feet deep will hold 5 times as much as one 12 feet 

 deep. 



Summer silos should be deeper in proportion than those intended 

 for winter use, because the silage spoils faster in summer and must 

 be fed down at the rate of about three inches a day to have always fresh 

 silage. 



Foundation. — This must start on level, firm earth, and should ex- 

 tend about 2 feet above the surface of the ground. If the foundation 

 is started deep the hole should be dug large enough to give ample room 

 outside of the wall to thoroughly tamp the earth up close to the founda- 

 tion. There is a tremendous outward pressure against this wall, es- 

 pecially in deep silos, and if it is not made strong it will crack and 

 admit air. It is also well to build' into the wall, about 18 inches above 

 the surface of the ground, several heavy wires to keep the wall from 

 cracking. It should be m.ade of stone or brick, laid in cement mortar, 

 or of concrete, and from 12 to 18 inches thick, depending on the height 

 the silo is to extend above it. 



Placed Partly in Ground. — It is a good plan to dig down 4 or 5 

 feet in order to secure good, firm earth on which to start the founda- 

 tion, and also in order to get the greatest capacity in the silo without 



