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Portrait after an engraving of Joseph Black (1728- 1799), Scottish chemist. Black studied medicine at Glasgow and Edinburgh, eventually achieving professorships at both. He went on to study kidney stones and similar minerals: he discovered that heating calcium carbonate gave calcium oxide and a gas, and that the products would recombine to form the carbonate. Moreover, he discovered that this gas was present in air, and would not support combustion. This gas was carbon dioxide. His precise measurements of this led to his idea of heat as a quantity, rather than intensity, and his later discovery of the concept of latent heats of vapourisation and melting.
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