Manchester Memoirs, Vol. xlii. (1898), No. 41 



4. The method of conducting the experiments was as follows : 

 During the progress of the experiments I had the 

 assistance of two men and a boy. The first of the men 

 had to keep the boiler pressure constant and attend 

 generally to the needs of the engine. The second had 

 charge of a small hand-brake, by means of which the 

 speed of revolution could be delicately adjusted, and 

 further, it was his duty to keep a constant pressure of air 

 in a receiver which was in direct communication with the 

 inner surfaces of the water vortices formed in the brake. 

 This receiver had been attached to the brake in place of a 

 former free communication with the atmosphere, which 

 would have allowed the water in the brake to boil away 

 when the temperature rose to 2I2°F. The boy's time was 

 fully occupied in charging the ice-cooler with ice. 



In the last series of experiments three similar trials, of 

 62 minutes duration each, were made per day, the engine 

 never being stopped after the start till all three trials were 

 completed. Consequently, what is said below as to the 

 starting of the engine, only refers to the first trial made 

 on any day. 



I. The pump and engine were started simultaneously, 

 the brake being therefore supplied with a stream of water 

 from the ice-cooler. The brake then automatically 

 adjusted the amount of the contained water till the load 

 floated steadily clear of the floor. The engine speed was 

 then adjusted to the requisite point, viz., 300 revolutions 

 per minute, as indicated by a speed gauge. 



II. The temperature of discharge of the water then 

 rose more or less quickly, on account of the work done on 

 it in the brake. By adjusting the regulating valve in the 

 supply pipe, the discharge temperature finally remained 

 steady at about 212'^F. The water supply to the stuffing- 

 box was also regulated so as to get the desired difference 



