158 THE TROUT 



water, and not with the bottom of the hatching-box. 

 Thus are all the eggs kept immersed to a uniform 

 depth, while the water, the moving spirit of your 

 apparatus, percolating through the tray at all points, 

 circulates freely round each individual egg. 



A similar tray is suspended in the same way in the 

 second compartment. Each tray is furnished with a 

 detachable cover made of blue calico stretched on a 

 light framework of charred deal, which serves to keep 

 the eggs in darkness. 



Not the least important part of the box is a 

 strong, closely fitting lid to prevent the incursion of 

 marauders, such as rats and mice. The lid is divided 

 longitudinally into two leaves hinged, one to each 

 side of the trough, and opening independently. The 

 hinges are so arranged as to allow each leaf, when 

 opened and folded back, to hang vertically, flat 

 against the side of the trough. Panels of perforated 

 zinc let into each half of the lid afford the necessary 

 ventilation. 



This model hatching-box with fittings complete 

 can be supplied at a cost of only forty shillings. In 

 the early days of fish culture the eggs were laid in 

 gravel in the hatching-boxes. The idea was to 

 conform as far as possible to the natural conditions. 

 The objections, however, to the use of gravel were 



