25 



the machine described in Silliman's Journal, vol. xx, 1831, and for the 



purpose of experimenting in regard to the second, I arranged around one 



of the upper rooms in the Albany Acad- rig. 7. 



emy a wire of more than a mile in 



length, through which I was enabled to 



make signals by sounding a bell, (fig- 



7.) The mechanical arrangement for 



effecting this object was simply a steel 



bar, permanently magnetized, of about 



ten inches in length, supported on a 



pivot, and placed with its north end 



between the two arms of a horse-shoe 



magnet. When the latter was excited 



by the current, the end of the bar thus 



placed was attracted by one arm of the horse-shoe, and repelled by the 



other, and was thus caused to move in a horizontal plane and its further 



extremity to strike a bell suitably adjusted. 



This arrangement is that which is alluded to in Professor Hall's letter* 

 as having been exhibited to him in 1832. It was not, however, at that 

 time connected with the long wire above mentioned, but with a shorter 

 one put up around the room for exhibition. 



At the time of giving my testimony, I was uncertain as to when I had 

 first exhibited this contrivance, but have since definitely settled the fact 

 by the testimony of Ilall and others that it was before I left Albany, and 

 abundant evidence can be brought to show that previous to my going to 

 Princeton in November, 1832, my mind was much occupied with the sub- 

 ject of the telegraph, and that I introduced it in my course of instruction 

 to the Senior class in the Academy. I should state, however, that the 

 arrangement that I have described was merely a temporary one, and that 

 I had no idea at the time of abandoning my researches for the practical 

 application of the telegraph. Indeed, my experiments on the transmis- 

 sion of power to a distance were superseded by the investigation of the 

 remarkable phenomena, which I had discovered in the course of these 

 experiments, of the induction of a current in a long wire on itself, and of 

 which I made the first mention in a paper in Silliman's Journal in 1832, 

 vol. xxu. 



I also devised a method of breaking a circuit, and thereby causing a 

 large weight to fall. It was intended to illustrate the practicability of 

 calling into action a great power at a distance capable of producing me- 



* See the Report of the Committee, page 96, and Proceedings of the Albany Institute, 



January, 1858. 



