238 Dr. W. Marcet. 



Weight of ice melted 97'46 grams. 



T. water from ice 10'92 



Calories recovered. 



From melted ice + 7699 



heat absorbed in water .... + 1064 

 of air in chamber .... 9 



,, ,, air in annular space . . + L 



copper (of chamber) . . + 875 



9630 

 (9 subtracted) 



Number of revolutions of agitators 342,305 



342,305' = 11717.... 



Unfortunately the heat produced by the revolving fans was not 

 found to be exactly proportional to the number of revolutions, or 

 rather squared revolutions, although the figures approximated to each 

 other much nearer on the same day than on different days. It was 

 therefore decided to make two* preliminary experiments with the 

 agitators on the same day as each calorimeter experiment, and to 

 subtract the agitator calories from the total calories obtained. As 

 the number of revolutions was not exactly the same in the test 

 experiments and in calorimeter experiments, the calories for correc- 

 tion were calculated in proportion to the revolutions in the test 

 experiment, of course previously squaring the revolutions. 



The following table shows in calories the heat produced by the 

 ventilators during forty minutes from a few experiments, the number 

 of revolutions is about 230,000, and the calories are calculated for 

 200,000 :- 



On 200,000 Eevolutions. 

 Date. Calories. Means. 



4th January, 1897 6866 



5974 



8th ' 2S} 







10th 5323, 



5551 



49011 



4658 / 



14th 61201 



5956 >6434 

 6463 J 



* When time was pressing only one was made. 



