Joseph Black (1728-1799) is one of the founders of modern chemistry, who made major discoveries regarding the different gases in the atmosphere and who invented a way to obtain accurate measurements of heat. From 1766 until 1799, he was Professor of Chemistry at the University of Edinburgh. His lectures circulated in manuscripts drawn up by his students. The image here shows a drawing of a thermometer made by one such student in 1784. Now such a familiar image, at the time it was a revolutionary device that transformed systematic research.