THE HATCHING APPARATUS. 15 



When filling up an apparatus a small " union " 

 metal pipe should be attached to the water supply and 

 carried along the whole length of the bottom edge of 

 each trough, being connected by small gas unions with 

 the supply pipe, as in sketch. The other, or free end, 

 is squeezed together with pincers, and thus closed 

 water-tight. Small perforations are then made with a 

 fine-pointed awl or other instrument, and this gives a 

 thorough aeration to the whole of the water in each 

 trough, and an equal supply of fresh water throughout 

 the apparatus. The spout of the bottom trough must 

 be connected by indiarubber pipe, or otherwise, to a 

 waste pipe leading to the drain, and of the same size 

 as the spout. 



PERFORATED ZINC INNER TROUGHS. 



