72 VETERINARY HYGIENE 



be placed as far from the buildings as can be arranged, but 

 consideration must be given to the labour involved. It must not be 

 placed near to a dairy or milk store or in close proximity to the 

 farmhouse itself, nor in the line of prevailing winds. The bottom 

 of the pit should be of cement concrete, and it should be surrounded 

 by a wall about four feet high with a break sufficiently wide to admit 

 a farm cart with ease. A corrugated iron roof will improve the 

 value of the manure by preventing dilution with excessive rain. If 

 the roof is placed too low the manure will get too hot and spoil. 



The liquids from all the animal buildings should be brought to 

 converge at one point if possible. At the point of convergence the 

 pipes should meet in an inspection chamber fitted with half pipes. 

 All drains should be laid so as to cause as little check as possible to 

 the even flow of the liquid. From this chamber one pipe should 

 carry the liquid to the settling chamber. The settling chamber should 

 be constructed of cement concrete throughout, or with a cement 

 concrete floor and walls of brick faced with cement. It should be 

 divided into two parts by a vertical plate passing from the top 

 down to the bottom and fitted into grooves at the sides and bottom. 

 The plate should be perforated so as to let the liquids pass through 

 to the distal side of the tank and retain the solids on the inlet side. 

 The outlet pipe leading to the liquid manure storage tank should 

 be bent down so as to dip into the liquid, thus forming a seal to 

 prevent the backflow of gases from the storage tank, thereby con- 

 serving the ammonia in the liquid manure. The storage tank must 

 be placed at a point suitable for the collection of the liquid and its 

 distribution to all parts of the farm ; close proximity to a roadway 

 is therefore desirable. Like the manure pit its location must be 

 such as not to create a nuisance. 



The size of the tank will naturally depend upon the size of the 

 farm and the number of animals kept. The Ministry of Agricul- 

 ture and Fisheries suggests an allowance of 12 to 15 cubic feet of 

 tank capacity per head of cattle. The following table of dimensions 

 is taken from a leaflet of the Ministry.* In the case of larger tanks 

 alternate measurements are given for deep or shallow tanks. 



*RP. 449/SI. 



