Construction of Brick-lined Silos. 403 



coat of cement plaster, one-fourth to one-half an inch thick, 

 and then this be kept whitewashed so as to neutralize the 

 acid and prevent it from softening the cement. 



3. The wall, or at least the inner portion, may be laid in 

 rich cement mortar, making the horizontal joints about one- 

 fourth of an inch thick and the vertical ones a half inch 

 thick, taking great care to get all joints of the inner tier of 

 brick thoroughly filled with mortar. This method will 

 place the cement where it will not be as readily affected by 

 the acids and frost and does away with the necessity of 

 plastering, care being taken to lay the brick smoothly and 

 to point the joints carefully. Milwaukee cement will answer 

 for this work. Whitewashing the inner face of such a 

 lining will be sufficient for smoothness and tightness. 



4. The very best possible lining which could be made 

 \vould be secured by using the small, thin size of vitrified 

 paving bricL These may be set on edge, to reduce both 

 the cost and the number of cement joints. It will be nec- 

 essary to tie this course occasionally to the main wall by 

 turning a brick endwise. Rich cement mortar should be 

 used and the joints made thin but thoroughly filled with 

 the mortar. Such a lining would give a surface like a stone 

 jug, thoroughly air-tight and indefinitely permanent. 



502, Doors. The jambs may best be made of 3x6's or 

 3x8's rabbetted two inches deep to receive the door on the 

 inside. The center of the jambs outside should be grooved 

 and a tongue inserted projecting three-fourths of an inch 

 outward Jo set back into the mortar and thus secure a thor- 

 oughly air-tight joint between the wall and jamb. 



The doors are best made as described under the stone silo, 

 of two layers of matched flooring with paper between. 



CONSTRUCTION OF BEICK-LINED SILOS. 



Next to the all-masonry silos in point of durability and 

 efficiency must be ranked the masonry lined silos, of which 



