Louis Jourdan wrote in USMA 12297: >In one of his experiments (artificial incubation of chicken eggs), >Réaumur needed to control very accurately the temperature, but was >not happy with the accuracy of the then available thermometers. >Therefore, in 1730-1731, he developed a new type of thermometer, with >alcohol as dilatating liquid. He used molten ice to define the cold >point, giving it the value 0, and boiling water for the hot point, >with the value 80. I could not find out why 80. My Encylopaedia Britannica, 11th Edition, says "The thermometer by which he is now best remembered was constructed on the principle of taking the freezing-point of water as 0°, and graduating the tube into degrees each of which was one-thousandth of the volume contained by the bulb and tube up to the zero mark. It was an accident dependent on the dilatabilty of the particular quality of alcohol employed which made the boiling-point of water 80°; and mercurial thermometers the stems of which are graduated into eighty equal parts between the freezing- and boiling-points of water are *not* Réaumur thermometers in anything but name." Joseph B. Reid 17 Glebe Road West Toronto M5P 1C8 Tel. 416 486-6071
