THE "WISCONSIN" SILO. 43 



If the silo has an inside diameter exceeding 15 feet it will be 

 necessary to use two or three hoops according to diameter. 



The conical roof may be covered with ordinary shingles, split- 

 ting those wider than 8 inches. By laying the butts of the shingles 

 % to % of an inch apart it is not necessary to taper any of the 

 shingles except a few courses near the peak of the roof. 



The prepared roofings, such as "Ruberoid" or "Parold" or pre- 

 pared gravel roofing are preferred to shingles for a silo roof, since 

 they make a tighter roof which retains the heat in winter. 



In laying the shingles to a true circle, and with the right 

 exposure to the weather, a good method Is to use a strip of 

 wood as a radius which works on a center set at the peak of the 

 roof and provided with a nail or pencil to make a mark on the 

 shingle where the butts of the next course are to come. The 

 radius may be bored with a series of holes the right distance 

 apart to slip over the center pivot, or the nail may be drawn and 

 reset as desired. Some carpenters file a notch in the shingling 

 hatchet, and use this to bring the shingle to place. 



Ventilation of the Silo. 



Every silo which has a roof should be provided with ample 

 ventilation to keep the under side of the roof dry, and in the case 

 of wood silos, to prevent the walls and lining from rotting. One 

 of the most serious mistakes in the early construction of wood 

 silos was the making of the walls with dead-air spaces, which, 

 on account of dampness from the silage, led to rapid "dry-rot" 

 of the lining. 



In the wood silo and in the brick lined silo it is important to 

 provide ample ventilation for the spaces between the studs, as 

 well as for the roof and the inside of the silo, and a good method 

 of doing this is represented in Fig. 4, where the lower portion 

 represents the sill and the upper the plate of the silo. Between 

 each pair of studs wherfe needed a. 1%-inch auger hole to admit 

 air is bored through the siding and sheeting and covered with 

 a, piece of wire netting to keep out mice and rats. At the top of 

 the silo on the inside, the lining is only covered to within two 

 inches of the plate and this space is covered with wire netting 

 to prevent silage from being thrown over when filling. This 

 arrangement permits dry air from outside to enter at the bdttom 

 between each pair of studs and to pass up and into the silo, thus 

 keeping the lining and studding dry and at the same time drying 

 the under side of the roof and the inside of the lining as fast as 

 exposed. In those cases where the sill is made of 2x4's cut in 



