1857] WRITINGS OF JOSEPH HENRY. 437 



not familiar with the then existing state of the science of electro-magnetism. 

 Had he been so, or had he read and appreciated the paper of Henry, the sug- 

 gestions made by me would naturally have occurred to his mind as they did 

 to my own. But the principal part of Morse's great invention lay in the 

 mechanical adaptation of a power to produce motion, and to increase or relax 

 at will. It was only necessary for him to know that such a powerexisted for 

 him to adapt mechanism to direct and control it. 



My suggestions were made to Professor Morse from inferences drawn by 

 reading Professor Henry's paper above alluded to. Professor Morse professed 

 great surprise at the contents of the paper when I showed it to him, but 

 especially at the remarks on Dr. Barlow's results respecting telegraphing, 

 which were new to him ; and he stated at the time that he was not aware 

 that any one had even conceived the idea of using the magnet for such pur- 

 poses. 



"With sentiments of esteem, I remain, vours trulv, 



L. D. Gale. 



Prof. Joseph Henry. 



Appendix B. — Letter from Prof. Hall. 



Albany, N. Y., January 19, 1856. 



Dear Sir : While a student of the Pvensselaer School, in Troy, New 

 York, in August, 1832, I visited Albany with a friend, having a letter of 

 introduction to you from Professor Eaton. Our principal object was to see 

 your electro-magnetic apparatus, of which we had heard much, and at the 

 same time the library and collections of the Albany Institute. 



You showed us your laboratory in a lower story or basement of the build- 

 ing, and in a larger room in an upper story some electric and galvanic ap- 

 paratus, with various philosophical instruments. In this room, and extend- 

 ing around the same, was a circuit of wire stretched along the wall, and at 

 one termination of this, in the recess of a window, a bell was fixed, while the 

 other extremity was connected with a galvanic apparatus. 



You showed us the manner in which the bell could be made to ring by a 

 current of electricity, transmitted through this wire, and you remarked that 

 this method might be adopted for giving signals, by the ringing of a bell at 

 the distance of many miles from the point of its connection with thegoilvanic 

 apparatus. 



All the circumstances attending this visit to Albany are fresh in my re- 

 collection, and during the past years, while so much has been said respect- 

 ing the invention of electric telegraphs, I have often had occasion to mention 

 the exhibition of your electric telegraph in the Albany Academy, in 1832. 



If at any time or under any circumstances this statement can be of service 

 to you in substantiating your claim to such a discovery at the period named, 

 you are at liberty to use it in any manner you please, and I shall be ready 

 at all times to repeat and sustain what I have here stated, with many other 

 attendant circumstances, should they prove of any importance. 

 I remain, very sincerely and respectfully, yours, 



James Hall. 



Professor Joseph Henry. 



