236 



FARM BUILDINGS IN SOUTH AFRICA 



6 inches thick (5£ inches 

 concrete, ^ inch cement 

 plaster). The inside dimen- 

 sions are those recommended 

 in the " Union " type of tank 

 (Agricultural Journal, Janu- 

 ary, 1913, p. 55), except that 

 the width of the tank at the 

 surface of the dipping fluid 

 is only 4 feet in place of 

 4 feet 6 inches. This dimen- 

 sion depends on the width 

 over the animal's horns; at 

 the Potchefstroom Experi- 

 mental Farm 4 feet is suffi- 

 cient. 



The tank is provided with 

 a concreted race and with 

 hinged flaps, which, when 

 raised, act as splash-boards, 

 and when lowered form a 

 roof that excludes rain and 

 minimises evaporation of the 

 dipping fluid. 



The following description 

 will serve as a guide to the 

 construction of the tank : — 



The Site. — From the con- 

 structional point of view the 

 site should be fairly level and 

 dry. The soil should be firm 

 enough not to cave in when 

 the excavation is made, i.e. it 

 should stand unsupported by 

 boarding or other assistance. 

 The earthen sides of the ex- 

 cavation then act as the outer 

 mould or " form " which 

 shapes the concrete. 



