1 8 Reynolds and Moorby, Equivalent of Heat. 



those already described, with a view to test the improved 

 facilities, also to gain experience and facility in making 

 and recording the observations. The engines being 

 otherwise engaged two or three days in the week, every 

 opportunity was valuable. 



At the same time, experiments were in progress to 

 ascertain the length of lin. pipe necessary in order that 

 water (2olbs. per minute) flowing through it might be 

 cooled from 212^ to 75°, when the pipe was jacketed by a 

 stream of town's water at 50^^. As the result of these a 

 condenser 30ft. long was constructed. 



After passing the condenser, the water was led verti- 

 cally to a height of 5 ft. above the chamber, thence past 

 an air gap down again to the switch, so as to maintain a 

 head of 5 ft. in the chamber, to prevent bubbles forming 

 in the water on account of the air it contained. This 

 height was subsequently raised to lift. 



In order to cool the water as nearly as practicable, 

 without danger of ice being carried over, the cooler was 

 designed so that the ice should be outside the pipe through 

 which the water passed. This clearly required a con- 

 siderable length of pipe, so that the resistance had to be 

 taken into account. As the result of experiments, 200ft. 

 of ^in. composition pipe was used in a coil, it being 

 estimated that this would pass 2olbs. a minute, with a loss 

 of pressure of 3olbs. on the square inch. This was placed 

 in a tank of parafiined wood, and a paddle worked by the 

 line shaft constantly circulated the water ; the arrange- 

 ment being designed to secure the coldest water passing 

 along the coil. 



To obtain the necessary head — 3olbs. for the coil, 5 

 for the brake, and 25 for regulation — it was necessary 

 to pump the water. It was also necessary that the flow 

 should be steady. To obtain these ends, recourse was had 

 to the 3in. quadruple turbine, driven by the water from 



