Hans Peter Jörgen Julius Thomsen, a Danish chemist, is noted for his early work in thermochemistry. Between 1869 and 1882, he carried out a great number of experiments to determine the amount of heat that evolved or absorbed in chemical reactions, such as in the formation of salts, oxidation and reduction, and the combustion of organic compounds. He was among the first to adopt the principle of the conservation of energy as the basis of a thermochemical system. In 1857, he established in Copenhagen a process for manufacturing soda from cryolite obtained from the west coast of Greenland.