524 THE POPULAR SCIENCE MONTHLY. 



tain nearly a pound weight, and which, when mounted as a part of the 

 instrument, performed the work of actuating *the armature with perfect 

 success. 



At quite an early age he was apprenticed to a blacksmith, and worked 

 with him at that business about one year. He found, however, that this 

 business was too laborious for him, and relinquished it to become an 

 apprentice to a carpenter, joiner, and boat-builder, with whom he served 

 a full apprenticeship, during which time he was employed in almost 

 every department of woodwork. The prime motive which actuated 

 him through all these years that he had worked at the bench was his 

 thirst for knowledge. He felt sure that, with his trade as his capital, 

 he could work his way through a course of study. In pursuance of 

 this idea, after the time had expired for which he had apprenticed him- 

 self, he began a regular course of study, and, by working a portion of 

 each day and during vacation at his trade, was enabled to pay his 

 necessary expenses and keep up with his class. Here, as everywhere 

 else, the capacity and ability to master everything relating to physical 

 science was perhaps the most prominent characteristic exhibited during 

 his collegiate course. While studying natural philosophy, it was his 

 custom to make and carry with him into the class such apparatus as 

 could be readily constructed and would serve to illustrate the lesson. 

 His habit of actually constructing everything which he saw or read of, 

 so far as his facilities would allow, was the best possible method of 

 fixing the principles of its operation firmly in his mind. 



Mr. Gray's career as a professional electrician and inventor dates 

 from the year 1865. His first patent for electrical or telegraphic appa- 

 ratus was granted October 1, 1867. Since that time he has made a con- 

 siderable number of electrical inventions, many of which have been 

 patented. Including cases now pending, the number amounts to about 

 forty in this country and thirty in foreign countries. Thirty of the 

 United States cases and twenty-five of the foreign relate to the tele- 

 phone. 



His attention was first called to the subject of telephonic transmis- 

 sion in the winter of 1867. In the course of his experiments during this 

 winter and spring, he made use of a vibrating electrotome or reed in 

 the primary circuit of an induction coil, and an electro-magnet having 

 a polarized armature, in the secondary circuit. A Morse transmitting 

 key was also inserted in the last-mentioned circuit. When the electro- 

 tome was in operation, and the Morse key in the secondary circuit was 

 closed, he noticed a singing sound in the electro-magnet, and, by work- 

 ing the key as if transmitting a Morse message, the signals were audibly 

 produced on the magnet by long and short sounds, representing the 

 dots and dashes of the Morse alphabet. He saw in it a method for 

 transmitting signals for telegraphic purposes, and also about the same 

 time conceived the idea of arranging a key-board, having electrotomes 

 tuned to the different tones in the scale. He did not, however, at this 



