BELL, Alexander Graham, physicist, born in Edinburgh, Scotland, 3 March 1847. He is a son of Alexander Melville Bell, mentioned below, and was educated at the Edinburgh high school and Edinburgh University, receiving special training in his father's system for removing impediments in speech. He removed to London in 1867, and entered the University there, but left on account of his health, and went to Canada with his father in 1870. In 1872 he took up his residence in the United States, introducing with success his father's system of deaf-mute instruction, and became professor of vocal physiology in Boston University. He had been interested for many years in the transmission of sound by electricity, and had devised many forms of apparatus for the purpose, but the first public exhibition of his invention was at Philadelphia in 1876. Its complete success has made him wealthy. His invention of the "photophone," in which a vibratory beam of light is substituted for a wire in conveying speech, has also attracted much attention, but has never been practically used. It was first described by him before the American association for the advancement of science in Boston, 27 August 1880. After the shooting of President Garfield, Professor Bell, together with Sumner Tainter, experimented with an improved form of Hughes's induction balance, and endeavored to find the exact location of the ball, but failed. Professor Bell has put forth the theory that the present system of educating deaf-mutes is wrong, as it tends to restrict them to one another's society, so that marriages between the deaf are common, and therefore the number of deaf-mute children born is on the increase. His latest experiments relate to the recording of speech by means of photographing the vibrations of a jet of water. He is a member of various learned societies, and has published many scientific papers. He has lived for some time in Washington, District of Columbia