80 



Some experiments were carried on with air as the fluid passing 

 through the pipes. With the nozzle and discs used there appeared to be 

 no governing- effect, in case of these air pressures. 



In general it may be said that the shape of the nozzle has most to 

 do with the action observed. A num))er of nozzles of different form were 

 used; those most nearly lilvc that shown on Fig. 2 gave the l>est governing 

 effect. 



The size of the disc affects the results obtained with any given nozzle. 

 Two-inch disc gave better results tlian 1-incli or the li/^-inch disc. 



The action desired could be oljtained with water at a, temperature of 

 75° P. as Avell as at the higher temperatures. 



A very pretty cylindrical sheet of water could be obtained l)y remov- 

 ing the lower part of the casing. The disc acted like the well-known liall- 

 nozzle. T'nder these conditions, witli a head pressure of 40 pounds and a 

 nozzle velocity (as figured from the discharge) of 14.G feet per second, it 

 was found necessary to exert a force of pounds to pull the disc from 

 the jet. 



WATER. 



