Daniel Gabriel Fahrenheit (24.05.1686- 16.09.1736) - physicist. Born in Danzig (now Gdańsk). From 1707 he travelled in Germany and acquired the trade of maker of various instruments. In 1717 he moved to Amsterdam, where he established himself as a maker of instruments and apparatus. He spent most of his life in Holland. He met and corresponded with the leading scientists of his time, in particular P. Musschenbroek, W. 's Gravesande and others. He organised a mechanical workshop in which he made thermometers, barometers, hydrometers and other physical and astronomical instruments. In 1709 he made a spirit thermometer, and in 1714 a mercury one. He proposed (1710 or 1714) a temperature scale (the Fahrenheit scale) in which the temperature interval between the melting point of ice and the boiling point of water was divided into 180 parts (degrees), the melting point of ice corresponding to the value 32 °F and the boiling point of water to 212 °F. Fahrenheit's thermometers were the first practically usable thermometers. He studied the supercooling of water (1721) and the dependence of the boiling point of a liquid on the pressure and on the content of salts dissolved in it. He designed a thermometer that made it possible to find the pressure from the boiling point. He determined the temperature of a mixture of hot and cold water. He improved the weighing hydrometer and compiled tables of the specific gravities of bodies (1724). Fellow of the Royal Society (1724).