On the original Celsius temperature scale of 1742 what was the boiling point of water?
The first half of the 18th century was a great time for inventing temperature scales.
In 1742 the Swedish astronomer Anders Celsius (1701–1744) created a temperature scale that laid the basis for the one that is almost universally used today. However, it had one feature that now seems extraordinary: higher numbers on the scale represented lower temperatures. Celsius's original scale was the reverse of the one now known as "Celsius" or "Centigrade": 0 represented the boiling point of water, while 100 represented the freezing point of water. This did not last.
The next year (1743), the French physicist Jean-Pierre Christin, permanent secretary of the Academy of Lyon, inverted the Celsius scale so that 0 and 100 represented the freezing point and the boiling point of water respectively. The Christin modification of the Celsius scale is essentially the one that is employed in the modern international scientific community and by the general public in almost all countries.
René de Réaumur (1683-1757), a French entomologist and writer made his contribution in 1730. The Réaumur temperature scale puts the freezing and boiling point of water at 0 and 80 degrees respectively. The Réaumur scale was once widely used in Europe, but died out by the early 20th century.
Daniel Gabriel Fahrenheit (1686–1736), a Danzig-born physicist proposed his scale in 1724. The Fahrenheit scale puts the freezing and boiling point of water at 32 and 212 degrees respectively.