210 



FARM BUILDINGS IN SOUTH AFRICA 



being laid while in a wet condition. If of stone, the walls should have 

 large through stones or bonders every 3 or 4 feet apart, measured hori- 

 zontally. Midway between each pair of bonders should be a header, 

 i.e. a stone extending from the face of the wall through at least two-thirds 

 of its thickness, the headers extending alternately from the inside face 



Fig. 163a. — Elevation of stone silo, looking in direction of arrow B (Fig. 163). 



and from the outside face of the wall. These bonders and headers should 

 break line vertically. 



The walls should be strengthened by building in strong hoop-iron 

 bands at frequent intervals. The lower part of the silo, and between 

 the emptying doors, should be specially strongly reinforced in this way. 

 The parts weakened by the emptying doors may be further strengthened 

 by building in long fencing standards above and below the doors. 



