Masterpieces of Science 



magnet and not by means of a needle galva- 

 nometer. 



At the conclusion of the series of experiments 

 which I described in Silliman's Journal , there 

 were two applications of the electro-magnet in 

 my mind : one the production of a machine to be 

 moved by electro-magnetism, and the other the 

 transmission of or calling into action power at a 

 distance. The first was carried into execution 



Fig. 7 



in the construction of the machine described in 

 Silliman's Journal, vol. xx, 1831, and for the pur- 

 pose of experimenting in regard to the second, I 

 arranged around one of the upper rooms in the 

 Albany Academy a wire of more than a mile in 

 length, through which I was enabled to make 

 signals by sounding a bell, (Fig. 7.) The me- 

 chanical arrangement for effecting this object was 

 simply a steel bar, permanently magnetized, of 

 about ten inches in length, supported on a pivot, 

 34 



