Meteorology known as the first "anemometer". In 1607, Galileo Galilei constructed a thermoscope. In 1611, Johannes Kepler wrote the first scientific treatise on snow crystals: "Strena Seu de Nive Sexangula (A New Year's Gift of Hexagonal Snow)". In 1643, Evangelista Torricelli invented the mercury barometer. In 1662, Sir Christopher Wren invented the mechanical, self-emptying, tipping bucket rain gauge. In 1714, Gabriel Fahrenheit created a reliable scale for measuring temperature with a mercury-type thermometer. In 1742, Anders Celsius, a Swedish astronomer, proposed the "centigrade" temperature scale, the predecessor of the current Celsius scale. In 1783, the first hair hygrometer was demonstrated by
Mercury silvering Mercury silvering Mercury silvering or fire gilding is a silvering technique for applying a thin layer of precious metal such as silver or gold (mercury gilding) to a base metal object. The process was invented during the Middle Ages and is documented in Vannoccio Biringuccio's 1540 book "De la pirotechnia". An amalgam of mercury and the precious metal is prepared and applied to the object which is then heated, sometimes in oil, vaporizing most of the mercury. The technique is dangerous since mercury is highly toxic, especially in its vapor phase. Mercury silvering can be detected through a variety of