. In 1732 Boerhaave of Leyden published the best chemical treatise of the time and thus helped to co-ordinate existing knowledge.
Most early work on chemistry sprang from a desire to explain the phenomena of flame. When bodies are burnt, it seems that something escapes. This something, for long called sulphur, was given the name of ‘phlogiston’ the principle of fire, by Stahl (1660-1734) , physician to the king of Prussia. Rey and Boyle had shown that when metals were burnt the solid increased in weight; thus, as Venel pointed out, phlogiston must possess a negative weight-a return to Aristotle’s idea of a body essentially light. Chemistry, ignoring the achievements of physics, learned to express itself in terms of phlogiston, which dominated the chemical thought of the latter part of the eighteenth century.