While he was struggling with these distracting calls of duty and science he was obliged to go to Washington to see his patent attorney. There he determined to call upon Professor Joseph Henry, who was the greatest American authority on electrical science, and who had experimented with the telegraph in the early years of the century. Bell, aged twenty-eight, explained his new idea to Henry, then aged seventy-eight. The theory was new to Henry, but he saw at once that it had tremendous possibilities. He told Bell so. “But,” said Bell, “I have not the expert knowledge of electricity that is needed.” “You can get it,” answered Henry. “You must, for you are in possession of the germ of a great invention.” Those few words, coming from such a man, were of the greatest possible encouragement to Bell. He returned home, determined to get the knowledge of electricity he needed, and to carry on his work with the telephone. He rented a room at 109 Court Street, Boston, for a workshop, and took a bedroom in the neighborhood. He studied electricity night and day, and he gave equal time to the musical telegraph that his friends favored and to the invention that now claimed his real interest. The man from whom Bell rented his workshop was Charles Williams, himself a manufacturer of electrical supplies. Bell had for his assistant Thomas A. Watson, who helped him construct the two armatures, or vibrating discs, at the end of an electrified wire that stretched from the workshop to an adjoining room. Watson was working with Bell on an afternoon in June, 1875. Bell was in the workshop, and Watson in the next room. Bell was stooping down over the instrument at his end of the wire. Suddenly he gave an exclamation. He had heard a faint twang come from the disc in front of him. He dashed into the next room. “Snap that reed again, Watson,” he commanded. Back at his own end of the wire he waited. In a minute he caught the light twang again. It was only what he had been expecting to hear at any time during the months of his work, but nevertheless he was amazed when he did catch the sound. It proved that a sound could be carried over a wire, and accurately reproduced at the farther end. And that meant that the vibrations of the human voice could ultimately be sent in the same way. Bell’s enthusiasm had already converted his assistant, Watson; it now won over Hubbard and Sanders. They began to believe that there might be something of real value in his strange scheme, and offered to help him finance it. He went on with his studies in electricity, and gradually began to learn how he could make it serve him best.