Joseph Black. Portrait of the Scottish chemist, physician and physicist Joseph Black (1728-1799). Black studied medicine at Glasgow and Edinburgh in Scotland, and was later a professor at both at various times. He studied calcium carbonate (CaCO3) and its related compounds, showing that heating CaCO3 gave calcium oxide and a gas, and that the products would recombine to form CaCO3. He also found that this gas (carbon dioxide) was present in air and would not support combustion. His precise measurements of this led to his idea of heat as a quantity, rather than intensity, and his later discovery of the idea of latent heats of vapourization and melting. From an 1833/37 book.