1816 - began work as an accountant in the firm owned by Charles Macintosh, the inventor of waterproof cloth. 1826 - appointed lecturer in chemistry at the Glasgow Mechanics' Institution. 1827 - became a medical student at Glasgow University and published his discovery of sodium pyrophosphate. 1833 - became professor of chemistry in the Marischal College, Aberdeen. 1841 - patented his method of water softening.