Thermometer of Lyon (1743).
Jean-Pierre Christin (May 31, 1683 – January 19, 1755) was a French physicist, mathematician, astronomer and musician. His proposal in 1743 to reverse the Celsius thermometer scale (from water boiling at 0 degrees and ice melting at 100 degrees, to where zero represented the freezing point of water and 100 represented the boiling point of water) was widely accepted and is still in use today.
Christin was born in Lyon. He was a founding member of the Académie des sciences, belles-lettres et arts de Lyon and served as its Permanent Secretary from 1713 until 1755. His thermometer was known in France before the Revolution as the thermometer of Lyon. One of these thermometers was kept at the Science Museum in London.