English inventor and physicist who designed several scientific instruments, including a very sensitive torsion balance used 1895 to determine Isaac Newton's gravitational constant and the mean density of the Earth.
Boys was born in Wing, Rutland, and studied at the Royal School of Mines, London. For a time he was on the staff of the Royal College of Science, London, then worked for the Metropolitan Gas Board 1897–39.
Boys elaborated on the Cavendish experiment to determine the gravitational constant and the mean density of the Earth. In Boys's apparatus copper wire was replaced by an extremely fine quartz fiber—made by firing an arrow to the end of which was attached molten quartz.
Boys’s other work included the invention of a “radio-micrometer” 1890 to measure the heat radiated by the planets in the Solar System. He also developed a special camera to record fast-moving objects such as bullets and lightning flashes, and devised a calorimeter which became the standard instrument used to measure the calorific value of fuel gas in Britain. In addition, he performed a series of experiments on soap bubbles, which increased knowledge of surface tension and of the properties of thin films.