490 Mr. J. P. Joule on the Heat disengaged 



Table I. 



Date of the 

 experiments. 



Sept. 4, 7 a.m. 

 Sept. 4, 7$ a.m. 

 Sept. 7, 7 p.m. 

 Sept. 7, 74 p.m. 



Number 



of cells 



in the 



pile. 



16 

 16 

 16 

 16 



Deflections of the 

 needle of the gal- 

 vanometer. 



Corrected 

 tangents of 

 the mean 

 deflections. 



72 17 I mean 



73 ljl. 

 72 47 T 

 72 58 J 



• 72 46 



3-2428 



Square of the cor- 

 rected tangents 

 reduced to facili- 



87-24 



Heat evolved in 

 >' in divisions of 

 the thermometer. 



81 94 



8913 



87-97 

 89-1)0 



mean 

 87-24 



Sept. 4, 7 p.m. 

 Sept. 4, 7J p.m. 

 Sept. 7, 7 a.m. 

 Sept. 7, 1\ a.m. 



61 81 

 61 26 

 60 19 

 60 28 



60 50£ 



1-8015 



26-92 



27-08 

 27-98 

 25-39 

 25-79 



26-56 



Sept. 5, 7 a.m. 

 Sept. 5, 74 a.m 

 Sept. 6, 7 p.m. 

 Sept. 6, 7-J p.m 



41 8 

 41 7 

 40 5 

 40 23 



40 41 



0-8634 



6-18 



6-23 

 6-27 

 5-76 



5-87 



603 



Sept. 5, 7 p.m. 

 Sept. 5, 74 p.m 

 Sept. 6, 7 a.m. 

 Sept, 6, 74 a-m 



25 57 

 25 504 

 24 40^ 

 24 18 



25 11 



0-4721 



1-85 



201 

 1-83 

 1-49 

 1-53 



1-71 



In order to carry on the experiments with electric currents of 

 feebler tension, I now introduced into the circuit an electrolytic 

 cell, consisting of two plates of zinc immersed in a solution of 

 sulphate of zinc. The results thus obtained are arranged in the 

 following table. In order to collect an appreciable quantity of 

 heat, the experiments were carried on for an hour with the lower 

 intensities, and for half an hour with the highest intensity of 

 current ; I have, however, reduced all the results to five minutes, 

 in order that they might be more readily compared with those 

 of Table I. Each of the results given in Table II. is the mean 

 of four experiments tried at different times, according to the 

 principles which guided me in the former experiments. 



Table II. 



