Page:Popular Science Monthly Volume 14.djvu/540

524 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 himself, 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 apparatus was granted October 1, 1867. Since that time he has made a considerable 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 telephone.

His attention was first called to the subject of telephonic transmission 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 electrotome was in operation, and the Morse key in the secondary circuit was closed, he noticed a singing sound in the electro-magnet, and, by working 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