THERMAL EFFECTS OF FLUIDS IN MOTION. 
359 
strokes of the pump to 27 per minute. The valves, fig. 3, consist of loose spheres of 
brass 0-6 of an inch in diameter, which fall by their own gravity over orifices 0*45 of 
an inch diameter. The cylinder and valves in connection with it are immersed in 
water to prevent the wear and tear which might arise from a variable or too elevated 
temperature. 
Fig. 1. 
Fig. 2. 
Fig. 3. 
Fig. 4. 
Wroiight-iron tubing, h b, fig. 1, of 2 inches internal diameter, conducts the com- 
pressed air horizontally a distance of 6 feet, thence vertically to an elevation of 
18 feet, where another length of 23 feet conveys it to the copper tubing, cc; the 
junction being effected by means of a coupling-joint. The copper tubing, which is 
of 2 inches internal diameter and 74 feet in length, is arranged in two coils, each 
being immersed in a wooden vessel of 4 feet diameter, from the bottom and sides of 
mdcccliij. 3 3 
