ON THE MECHANICAL EQUIVALENT OF HEAT 



391 



small particles of ice from flowing out. The whole was then covered 

 with cloth, to prevent melting. The vessel was then filled with water, 

 and the two thermometers immersed to get the zero points. The 

 calorimeter being about two-thirds filled with water, and having been 

 weighed, was then put in position, the holes corked up, and one ther- 

 mometer placed in it, the other being in the melting ice. An obser- 

 vation of its temperature was then taken every minute, it being fre- 

 quently stirred. 



FIG. 4. 



When enough observations had been obtained in this way, the cork 

 was taken out of the aperture F and the spout inserted, and the water 

 allowed to run for a given time, or until the calorimeter was full. It 

 was then removed, the cork replaced, and the second thermometer 

 removed from the ice to the calorimeter. Observations were then 

 taken as before, and the vessel again weighed. 



Two thermometers were used in the way specified, so that one might 

 approach the final temperature from above and the other from below. 

 But no regular difference was ever observed, and so some experiments 



