THE SILO. 



407 



STONE SILO. 



When stone is cheap and a long-lived silo the object, the stone 

 silo may be the most economical. 



That portion of the stone work which lies below the surface of 

 the earth should be laid in cement rather than lime mortar. Lime 

 sets very slowly under ground. "After the wall is 2 feet above ground 

 a good lime mortar may be used, but in this case there ought to be 

 at least two months for the wall to season and set before filling." 



Figure 4. Shows construction of stone silo. The basement "A" is a little too dee^ 

 for any but bank barns. "B" shows a cross-section of the silo. "C" and "D" the door 

 way. "E" the door in side view and end view. "F" the door in place. 



(After King.) " 



The wall at the bottom should be i8 inches in thickness and at top 12 

 or ten inches, the narrowing being made on the outside, the diameter 

 inside being kept the same all the way up. See figure 4. 



The Missouri Experiment Station built a stone silo in the summer 

 of 1905. It is 20 feet in diameter and 40 feet high, holds about 275 

 tons. The wall is 18 inches in thickness, laid up in lime mortar. 

 Above and below the five openings in the silo one-half inch iron rods 

 are built into the wall in the form of hoops to keep it from springing 

 or cracking. The inside is plastered smooth with Portland cement 

 mortar. For the construction of this silo there were required, ap- 

 proximately, J 20 perch of stone. The average cost of labor in con- 

 struction was $3.50 a perch. The first cost seems great, but with an 

 occasional whitewashing with cement inside to fill the small checks, it 

 ought to last a hundred years. This is the silo referred to as having had 

 no roof during the fall rains. See figure i. 



