Thermometer with double scale: Réaumur and centigrade, mounted on walrus tusk and circular ivory base. Complete with original tube, in very good condition, ivory turning yellow from age. See images for own impression. The Ráumur scale is named after René Antoine Ferchault de Réaumur, who first proposed a similar scale in 1730. In 1794 the French government chose the centigrade scale as part of the new decimal metric system. Height: 18,5 cm, diameter: 3,8 cm (base). The Certificate will be included with the shipping (see last image). Shipping: only within the EU (registered and insured). This item can not be shipped to any country outside the EU.