Delisle
The Delisle scale (°D) is a temperature scale invented in 1732 by the French astronomer Joseph-Nicolas Delisle (1688–1768). In 1732, Delisle built a thermometer that used mercury as a working fluid. Delisle chose his scale using the temperature of boiling water as the fixed zero point and measured the contraction of the mercury (with lower temperatures) in hundred-thousandths. Delisle thermometers usually had 2400 or 2700 gradations, appropriate to the winter in St. Petersburg, as he had been invited by Peter the Great to St. Petersburg to found an observatory in 1725.
Source: Wikipedia