20 



DEPARTMENT OF AGRICULTURE. 



farther from the nail than half the diameter of the silo. Keep the sweep true by 

 means of a level and draw the circle. Excavate within the circle to the depth of 

 4*0 feet, keeping the wall sloping slightly outwards and having the bottom level. 

 Then mark off another inch the exact size of the inner diameter, using the same 

 circle. Drive stakes, with their outer edge on this circle,around the silo about 2 feet 

 apart and brace them from the middle. Then bind thin boards around the outside 

 of these stakes. This constitutes the inner form of the foundation, the earth wall 

 being the outer. Before completing this, cut under the bank to give footing to the 

 foundation. Drainage for the foundation te; ds to prevent settling. A tile drain 

 around the outside of the footing would remote any water that might accumulate. 



&&$?* - ' _1 " - - 

 < /B>K*V> /.*r J c T-l 



m I 



i " " 









Fig. 13 (1). Foundation. 



Fig. 13 ' - 



FORMS. 



The metal forms or silo curbs undoubtedly will give better satisfaction than 

 the wooden forms, but unless there are a number of concrete silos to be erected in 

 a district they would prove expensive. 



Directions for constructing Wooden Forms. When metal forms are not avail- 

 able wooden forms may be constructed. In constructing wooden forms, first make 

 two circles on a barn floor or some level place to represent the inner and outer circle 

 of the wall of the silo to be built. This can be done with a sweep pivoted to a 

 central point with two nails through the end to act as markers. The two nails 

 should be not less than 6 inches apart, for it is not wise to build a wall less than 

 6 inches thick. By tacking wide boards lightly to the floor as shown in the diagram, 

 the patterns can then be marked with the sweep and scratching nails. It has been 

 found convenient to build the forms in sections one-sixth the circumference of the 

 silo. The distance between the central pivot and the outside scratch will divide 

 the outside circumference into six equal parts. An outside and inner form must 

 be built for each section. By tacking two boards S inches wide and 4 feet long 

 opposite each other, as suggested in the diagram, an inner and outer pattern can 

 be marked at the same time with the sweep. Two of these should be bolted 

 together to complete the pattern for a section. Each outer and inner sectional 

 form should be built 3 feet or 3 feet 6 inches high, using three sectional patterns 

 faced with metal sheeting or matched lumber. To hold the patterns together and 

 to give strength and rigidity to the forms. 2- x 4-inch material may be used. The 

 ends of the sectional forms should be sawn in a line from the centre of the silo 



