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A MODE OF REGULATING THE SUPPLY OF WATER BE- 

 TWEEN INTERSECTING RIVULETS AND CANALS. 



DEVISED BY THE LATE ROBERT ALMOND, ESQ. 

 of Nottingham. 



[Communicated by MARSHALL HALL,M.D.,F.R.S.E,,&c.&c.] 



rPHE Nottingham and Erewash canals diverge from the same 

 point, at Langley Mill, in the county of Derby, and are 

 terminated at the distance of a few miles from each other, by 

 the river Trent. In consequence of this relative situation, the 

 Nottingham, which was cut most recently, intersected some of 

 the rivulets which had previously fallen into the Erewash. To 

 compensate for this injury, an eminent mathematician devised 

 the following ingenious plan of delivering from a reservoir of 

 the Nottingham Canal, a given quantity of water per minute, 

 under every variation of the height of water in the reservoir. 



The water is brought into a small cistern, of which A (Fig. 1.) 

 represents part of the end. b is an aperture, parallel with the 

 horizon, which would of itself deliver the stipulated quantity 

 when the water in the cistern is at its greatest height, a is a 

 vertical aperture, connected with the former, and is quite 

 closed by the shuttle B, when the cistern is full. Its sides are 

 of that peculiar curvature, that as the shuttle is raised by the 

 action of the buoy C, descending with the surface of the water 

 in the cistern, the additional part of the aperture disclosed 

 exactly compensates for the diminution of pressure. This plan, 

 however, though correct in theory, proved altogether abortive 

 in practice, on account of the excessive friction which is pro- 

 duced, partly by the motion of the shuttle in a groove, and 

 partly by the lateral pressure of that portion of the water which 

 is above the disclosed part of the orifice*. 



A dispute afterwards arising respecting the Gilt Brook, 

 which the Erewash Company deemed valuable in the dry 

 summer months, and which had formerly been one of their 

 feeders, they demanded a regular supply of water, according 

 to the average quantity which the brook should be found to 

 deliver in the months of June, July, and August. This quan- 



* The investigation of the curve proper for the sides of the aperture, is furnished 

 ty the inventor m the < Gents. Diary for 1799.' 



