420 Rural Architecture. 



short and there are too many other things to engross the at- 

 tention of good farmers for them to lie awake nights won- 

 dering whether the silo hoops are too tight or too loose. 



3. Staves do not contain the same amount of sapwood in 

 all parts and for this reason shrink unequally, with the re- 

 sult that after 3 or 4 years' use there are places which do 

 not close up tightly on swelling and which open again on 

 the sunny side of the silo, and thus admit air, even where 

 the silage is in contact with them. 



Three of the silos visited showed these peculiarities, and 

 in one of them visited last winter we could see through be- 

 tween several staves on the south side of the silo close to the 

 silage surface, on the inside. 



4. The expansion and contraction of the staves during 

 wetting by the silage and drying when the silo is empty 

 makes it olifficult to securely anchor a permanent roof and 

 impossible to connect the staves permanently with the foun- 

 dation, so as to be air-tight. Something must be done each 

 season to cement the joints between the staves and foun- 

 dation or air will enter. 



5. There is no reason to hope that good silage with small 

 losses in dry matter can be made in the stave silos which 

 are not carefully constructed of good lumber with the 

 staves both beveled, &nd tongued and grooved. It is really 

 more difficult to make a stave silo air tight than it is to 

 make a tank water-tight, and we have found by careful 

 tests that the unavoidable losses in a new stave silo next to 

 the walls were as high as 24 to 28 per cent. 



510. Construction of Stave Silos. There are three meth- 

 ods adopted in the construction of these silos. The best 

 and only one which should be used in the permanent silo 

 is that represented in Fig. 208, where the staves are both 

 beveled and tongued-and-grooved; the second is where the 

 staves are beveled so that the flat surfaces fit together ac- 

 curately as water tanks are made; the third plan uses the 

 lumber without either beveling or tonguing-and-grooving, 

 and this both observation and principles of construction in- 



