pected 

 series. 



of Magneto-Electricity. 271 



to obtain the calorific effect of 1*019 in the new 



No. 4. 



It seemed to me very desirable to repeat the experiments, 

 substituting steel magnets for the stationary electro-magnets 

 hitherto used. With this intention I constructed two mag- 

 nets, each consisting of a number of thin plates of hard steel, 

 — an arrangement which we owe to Dr. Scoresby. My metal 

 was, unfortunately, not of very good quality, but nevertheless 

 an attractive force was obtained sufficiently powerful to over- 

 come the gravity of a small key weighing 47 grs., placed at 

 the distance of three-eighths of an inch. The following re- 

 sults were obtained by revolving the small compound electro- 

 magnet between the poles of the steel magnets. 



In order to obtain the whole calorific effect of the steel mag- 

 nets, I now, as in Series No. 4, connected the terminal wires 

 of the revolving electro-magnet, and interpolated the experi- 

 ments with others in which that connexion was broken. The 

 resistance of the coil of the revolving electro-magnet being to 

 the resistance of the whole circuit used in the experiments 

 marked No. 5 as 1 : 1*44, and 0-236 of current electricity 

 being obtained in those experiments, I expected to obtain in 

 the present series the calorific effect of 0*34 of current mag- 

 neto-electricity. 



