IV. IIYDEAULICri. 461 



that vary when the quantity flowing varies. It results that the quantity 

 flowing is proportional to the -| power of the vertical depth from the still 

 water surface level down to the vertex of the notch. The apparatus exhi- 

 bited shows two V notches, one without floor, and the other with a level floor 

 starting from the vertex of the notch. The introduction of the floor allows of 

 trustworthy gauging* being attained without the requirement of so deep a 

 pool as is otherwise necessary. For further information reference may be 

 made to British Association Report, Part I., Manchester Meeting, 1861. 



1995. Weisbach's Apparatus, for illustrating experimentally 

 the laws of Hydraulics, and for the determination of hydraulic co- 

 efficients. The Royal Indian Engineering College. 



Large Reservoir, with fittings for attaching mouth-pieces 

 under different heads. With hook gauges for marking the change 

 of water level. The Royal Indian Engineering College. 



Smaller Reservoir, for attachment to larger reservoir ; 

 used for experiments on large orifices and notches under constant 

 head. The Royal Indian Engineering College. 



Gauging Tank, fitted with Hook Gauges. 



The Royal Indian Engineering College. 



Reservoir and Long Channel, for illustrating the laws of 

 flow in open channels. 



The Royal Indian Engineering College. 



Series of Mouth-pieces and Orifices for use with the 

 reservoirs. Comprising 



3 large rectangular orifices and notches. 



6 thin edged orifices of different forms. 



6 conoidal and conical orifices. 



6 orifices with partially suppressed contraction. 



elbows, bends, and sudden enlargements. 



1 pair of plates for radial current. 



The Royal Indian Engineering College. 



4O9g. Darcy-Pitot Gauge, or current meter used in Darcy 

 and Bazin's researches on the flow of water in pipes and channels. 

 This gauge gives the velocity at a definite point of the stream and 

 without a time observation. P ro f- W. C. Unwin. 



2O64b. Professor James Thomson's Jet Pump, with 

 intermittent reservoir for drainage of low lands or shallow lakes 

 by water power. Prof. James Thomson. 



The jet pump, while working, must always have its full supply of water ; 

 but the intermittent reservoir allows of its varying its work according to the 

 wetness of the weather. 



The jet pump with intermittent reservoir is a contrivance for the drainage 

 of flat marshy lands, or shallow lakes, in cases in which there is no outlet 

 available low enough to allow of the water flowing away by its own gravita- 

 tion in drains of ordinary kinds, but in which there is water power available 



