ON THE MECHANICAL EQUIVALENT OF HEAT. 
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to the spindle at E. A piece of thin rubber tubing, F, was bound tightly to the 
ring, D, and the cork, E. 
This tube caught all the leakage, which then drained down the smaller tube (shown 
in the sketch) into a bottle standing on the floor. 
To prevent evaporation, the end of this small tube contained a short length ol glass 
tube, the capillarity of which always kept the end closed by a bead of water. 
General Arrangement of the Final Apparatus. 
15. The general arrangement of the apparatus, as tinally set up, is shown in the 
plates attached to Professor Reynolds’ paper (Part I.), and in the annexed diagram. 
The course of the water was as follows :— 
It was drawn from the mains by the circulating pump. A, and forced through the 
ice cooler, B, to the main regulating valve, C. Between the ice cooler and this valve 
there was a Bouidon pressure gauge and a branch-pipe, D, supplying water to the 
