1820 - sent from India to be raised by an aunt in St Andrews.

1832 - entered the University of St Andrews.

1835 - sent to Glasgow to train, unsuccessfully, as a merchant with his uncle James.

1837 - travelled to Calcutta, where work as a merchant's clerk had been arranged for him.

1838 - returned to England and became a laboratory assistant to the professor of chemistry, Thomas Graham at University College, London.

1841 - took his PhD and helped found the Chemical Society in Britain.

1845 - moved to London on becoming chemist to the Geological Survey.

1848 - elected as a fellow of the Royal Society.

1851 - during the Great Exhibition, he managed the prize-awarding juries and attended to the royal family. 1853 - was appointed as secretary for science, alongside Henry Cole as secretary for art, in the newly constituted Department of Science and Art.

1858 - took up the professorship of chemistry at Edinburgh University.

1870 - invented the postcard.

1873 - appointed postmaster-general.

1877 - travelled to the USA.

1883 - made Knight Commander (KCB).

1885 - served as president of the British Association for the Advancement of Science.

1892 - created Baron Playfair of St Andrews.

1895 - appointed Knight Grand Cross (GCB).

1897 - proposed the creation of a new museum at South Kensington, proposing the title ‘Victorian Museum’ in honour of the queen's jubilee.