754 



THE COMPLETE GRAZIER. 



BOOK VIII. 



and it is surprising that the former is not more commonly made than 

 it is in this country in wet seasons. Second crops of clover and grass, 

 moreover, as well as coarse herbage from waste land, might be made 

 into satisfactory silage when they cannot be converted into good hay. 

 Partly for this reason, and partly for the information of colonial and 

 foreign readers, we retain the description of the system given in our 

 last edition. At first it was considered necessary that an expensive air- 



Fig. 319. Wilson's Furcated Hydraulic Jacks as applied to a Silo. 



tight underground building a genuine silo should be set apart for the 

 process, as it was expected that the lateral pressure would burst any 

 ordinary walls, but it was soon shown that the difficulty was to get the 

 pressure sufficiently to the outside, as the shrinkage was always towards 

 the centre. Hence, silos came to be built above ground, but the cost of 

 these buildings was prohibitive of the rapid extension of the system. 

 It has since been proved that even air-tight buildings are unnecessary, 



