of Magneto-Electricity. 



269 



inches long, weighing 4 grains, would jump from a distance 

 of 3^ inches. 



Having fixed the electro-magnet just described with its poles 

 upwards, and on opposite sides of the revolving electro-magnet, 

 I arranged to it the battery often cells, in a series of five double 

 pairs, and, experimenting as before, I obtained a second series 

 of results. The galvanometer used in the present instance 

 was in every respect similar to that previously described, with 

 the exception of the coil, which now consisted of a single turn 

 of thick copper wire. Great care was taken to prevent, by 

 its distance from, and relative position with the electro-magnet, 

 any interference of the latter with its indications. 



No. 2. 



Revolu- 

 tions of 

 Electro- 

 Magnet 



per 

 minute. 



Deflec- 

 tions of 

 Galvano- 

 meter of 

 one turn. 



Mean 

 Tempe- 

 rature of 



Room. 



Mean 

 Differ- 

 ence. 



Temperature of 

 Water. 



Before. 



After. 



Loss or 

 Gain. 



Battery in 

 connexion. 



Battery con- 

 tact broken. 



Battery in 

 connexion. 



Battery con- 

 tact broken. 



Battery in 

 connexion. 



Battery in 

 connexion. 



Battery con- 

 tact broken. 



Battery in 

 connexion. 



J600 

 J600 

 1 600 

 1-600 

 J600 

 J600 

 J600 

 1-600 



22 

 



24 

 



24 45 



22 

 



21 20 



58-93 

 59-60 

 59-55 

 59-45 

 58-30 

 57-74 

 58-35 

 58-73 



Mean, 

 Battery in 

 connexion. 



Mean, 

 Battery con- 

 tact broken. 



600 



600 



22 49 







017+ 

 0-40 + 

 1-23+ 

 019+ 

 005+ 

 0-32+ 

 0-49+ 

 0-78+ 



58-20 

 60-02 

 59-90 

 59-78 

 57-35 

 57-28 

 58-83 

 58-83 



60-00 

 59-98 

 61-67 

 59-50 

 59-35 

 58-83 

 58-85 

 60-20 



1-80 gain 

 0-04 loss 

 1-77 gain 

 0-28 loss 

 2-00 gain 

 1-55 gain 

 0-02 gain 

 1-37 gain 



0-51 + 



0-36+ 



1-70 gain 

 010 loss 



Corrected 

 Result. 



1 600 22° 49' = 0-902 of cur. 



inag.-elect. 1-84 gain 



The corrected result is obtained as before, by adding the 

 loss sustained when contact with the battery was broken, to 

 the heat gained when the battery was in connexion. I have 

 in the present instance, however, made a further correction of 



