146 



SEASON 1874-75. 



pipes, one a waste stand-pipe, and the other an india-rubber supply- 

 pipe, for the slate-trays (Fig. 103). These pipes were inter- 

 im ay*"- >| changeable, so that the supply could be given 

 either to a right- or left-handed tray. The 

 mouth of the india-rubber pipe was supported by 

 a cork, so as to take only the top water, and 

 allow the slate cistern to act as a settling-tank 

 (Fig. 104). Taps were fixed on both pipes below 

 the bottom of the cistern. Below the cistern I 

 placed a stand supporting a set of six slate trays 

 (Fig. 112), and a slate filter similar to the one 

 figured on page 114. 



These trays I fitted with grilles, made also 

 of slate, as in so small grilles wood frames are 

 FIG. 103-scaie A. apt to float. The glass rods ran longitudinally. 

 The flexion of the tubes was overcome by silver wire laced across 



FIG. 104 scale ^. 



the centre. For experimental work these grilles offer certain 

 advantages, as they enable small quantities of eggs to be 

 segregated, and several experiments in contiguous troughs are 

 sufficiently close together to be compared at a glance. The slate 

 and glass grille is also very easily handled, and can be removed 



