Encyclopædia Britannica, Ninth Edition/Gabriel Daniel Fahrenheit
FAHRENHEIT, Gabriel Daniel (1686–1736), well known for the improvements made by him in the construction of the thermometer and barometer, was born at Dantzic, May 14, 1686. He early relinquished trade for the study of natural philosophy; and, after having travelled in Germany and England, he settled in Holland, where Gravesande and other men of science were his teachers and friends. In 1714 he conceived the idea of substituting mercury for spirits of wine in the construction of thermometers. He took as the zero of his thermometric scale the lowest temperature observed by him at Dantzic during the winter of 1709, which he found was that produced by mixing equal quantities of snow and sal-ammoniac. The space between this point and that to which the mercury rose at the temperature of boiling water he divided into 212 parts. At the time of his death, which took place on September 16, 1736, Fahrenheit was engaged in the contrivance of a machine for draining inundated land. See Thermometer and Meteorology.