PRESERVATION OF SILOS. 81 



mop or small whisk broom cut short, so it is stiff, may serve for 

 putting on the tar. 



Coal tar and gasoline have also been used by many with 

 good success. About half a gallon of coal tar and two-thirds 

 of a gallon of gasoline are mixed at a time, stirring it while it 

 is being put on. Since gasoline is highly inflammable, care 

 must be taken not to have any fire around when this mixture 

 is applied. Asbestos paint has also been recommended for the 

 preservation of silo walls, and would seem to be well adapted 

 for this purpose. 



Many silos are preserved by application of a mixture of equal 

 parts of boiled linseed oil and black oil, or one part of the former 

 to two of the latter. This mixture, applied every other year, be- 

 fore filling time, seems to preserve the lining perfectly. In build- 

 ing round silos, it is recommended to paint the boards with hot 

 coal tar, and placing the painted sides face to face. 



Manufacturers of stave silos and fixtures put up special 

 preparations for preserving the silos, which they send out with 

 the staves. These are generally simple compounds similar to 

 those given in the preceding, and are sold to customers at prac- 

 tically cost price. 



Walls of wooden silos that have been preserved by one or 

 the other of these methods will only keep sound and free from 

 decay if the silos are built so as to insure good ventilation. 

 Preservatives will not save a non- ventilated silo structure from 

 decay. 



Plastered wooden silos are preserved, as we have seen, by 

 applying a whitewash of pure cement as often as found neces- 

 sary, which may be every two or three years. The same applies 

 to stone and cement silos. The degree of moisture and acidity 

 in the silage corn will doubtless determine how often the silo 

 walls have to be gone over with a cement wash; a very acid 

 silage, made from immature corn, will be likely to soften the 

 cement coating sooner than so-called sweet silage made from 

 nearly mature corn. 



A considerable number of woad silos are in use that were 

 not treated on the inside with any preservative or paint and 

 have stood very well. Indeed, some writers maintain that if 

 the silo is well protected on the outside, a stave silo receives little 

 if any benefit from inside coatings. 



