FOR PLEASURE AND PROFIT. 



CHAPTER IV. 

 SCREENS AND SLUICES. 



The importance of properly constructing screens and sluices 



and most carefully fixing them cannot be over-estimated. To 



a very large extent the success of your operations 



depends upon proper control of the water supply, and this 



control occurs principally in connection with the screens and 



i sluices. And the first word of advice I shall give you about 



them is, Avoid complicated apparatus ; let your arrangement 



cf screens and sluices ba as simple as possible, so long a.s it 



j is effective, and let them be substantially put into position 



A screen should not receive the current, and, consequently, 

 j the debris brought down by it, " full face," unless it is 

 absolutely unavoidable. Screens should either slant up 

 from the bottom to the top, away from the current, or they 

 should be placed at an acute and obtuse angle not right 

 angle across the stream. Sluices should invariably be ar- 

 ranged so that the water 1 is drawn off from the surface, other- 

 wise difficulties are bound to crop up. These are the two prin- 

 cipal matters to bear in mind ; but other minor points arise in 

 connection with the erection of sluices and screens, and these 

 are dealt with, as they occur, in the following description of 

 approved apparatus. 



The first illustration in connection with this subject is a 

 photograph of a controlling sluice as fixed in a pond, and in 

 the illustration the pond is empty. Figs. 12, 13, and 14 are 

 sections of the contrivance, which has for its object the adjust- 

 ment of the water in a pond any height and the emptying of 



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