Thermometer 1665 Christiaan Huygens (1629–1695) suggested using the melting and boiling points of water as standards, and in 1694 Carlo Renaldini (1615–1698) proposed using them as fixed points on a universal scale. In 1701, Isaac Newton (1642–1726/27) proposed a scale of 12 degrees between the melting point of ice and body temperature. In 1714 Dutch scientist and inventor Daniel Gabriel Fahrenheit invented the first reliable thermometer, using mercury instead of alcohol and water mixtures. In 1724 he proposed a temperature scale which now (slightly adjusted) bears his name. He could do this because he manufactured thermometers, using mercury (which has a
Mercury-in-glass thermometer drops to may be used. , many mercury-in-glass thermometers are used in meteorology; however, they are becoming increasingly rare for other uses, as many countries banned them for medical use due to the toxicity of mercury. Some manufacturers use galinstan, a liquid alloy of gallium, indium, and tin, as a replacement for mercury. The typical "fever thermometer" contains between of elemental mercury. Swallowing this amount of mercury would, it is said, pose little danger but the inhaling of the vapour could lead to health problems. In February 2009, the Argentine Health Ministry instructed by resolution 139/09 that all health centres