92 



SEASON 1873-74. 



may be. This zinc screen clogged up very shortly after the box 

 was in use, and I altered its position from across the end of the 

 box to the top of the trough. This was the first step towards 

 inventing the leaf-screen (see page 108). The lid of the box was 

 covered with fine wire-netting to keep out birds, and a square 

 cut was made in the lower end, furnished with a shoot to 

 enable the water to be caught, and used in other boxes if desired. 



2' 2" 



FIG. 31 scale -fa. 



A hole was bored in this end near the bottom, to run off the water 

 when it was wished to clean the box, a plug of wood (Fig. 31) 



being inserted when the box was in 

 use. The outlet was guarded with per- 

 forated zinc (Fig. 32) one number larger 

 than the inlet, so as to ensure its always 

 keeping free. The Francis box did not 

 prove satisfactory as a hatching- box, 

 but it is admirable as a stew, and fish 

 can be fed and kept for weeks in it 



FIG. 32 scale ^. _ 



safely, which is not the case with the 

 ordinary floating stew used at Loch Leven for trout. 



SLATE TRAYS. 



I got a dozen slate trays made in Leith 20 inches by 5 inches 

 inside measurement. The sides and ends were grooved to receive 

 the bottom, and the sides were further grooved to receive the ends. 

 The tray was held together by four iron rods, two passing through 

 each end as close to the slate as the groove in the sides would 



