4 Reynolds and Moorby, Equivalent of Heat. 



blast, capable of running steadily at any speeds up to 400 

 revolutions a minute, and working up to 100 H.P., 

 especially arranged to give access to the shaft three feet 

 above the floor. 



(2) A special hydraulic brake dynamometer, on an 

 extension of the engine shaft. This brake, which is shown in 

 Figs. I and 2, is capable of absorbing any power up to a 

 maximum of 30 H.P. at 100 revolutions a minute, increasing 

 as the cube of the speed, so that it is capable of absorbing 

 the whole power of the engines at any speed above one 

 hundred revolutions a minute. 



The whole of the work is absorbed by the agitation of 

 the water contained in the brake, while the heat so 

 generated is discharged steadily by a stream of water 

 through the brake, with no other functions than of affording 

 means of regulating the temperature of the brake, and 

 the quantity of water in it. The moment of resistance 

 of the brake is a definite function of the quantity of 

 water it contains. And as, except for this moment, the 

 unloaded brake is balanced on the shaft, the load being 

 suspended from a lever on the brake at four feet 

 from the axis of the shaft, if the moment of resistance 

 of the brake exceeds the moment of the load, the lever 

 rises and vice versa. By making the lever actuate valves 

 which regulate the inlet and outlet streams, the quantity 

 of water in the brake is continually regulated to that 

 which is just sufficient to suspend the load with the lever 

 horizontal, and a constant moment of resistance is thus 

 maintained whatever may be the speed of the engines. 



(3) Manchester Town's water, of a purity expressed 

 by not more than 3 grains of salts to the gallon, brought 

 into the laboratory in a 4in. main at town's pressure (25 

 to 5olbs. per square inch), and distributed either direct 

 from the main, or at constant pressure from a service tank 

 I oft. above the floor of the laboratory. 



