1-151-880 - Ann Ronan Picture Library/Heritage-Images

Dalton's table of atomic symbols, 1835. A table of atomic symbols from a lecture delivered by the English chemist John Dalton (1766-1844) at the Manchester Mechanic's Institution, 19 October 1835. It includes symbols for individual elements as well as compounds. In 1803 Dalton formulated his atomic theory to explain chemical reactions, based on the concept that atoms of different elements are distinguished by differences in their weights.