Francis William Aston FRS (1 September 1877 – 20 November 1945) was a British chemist and physicist who won the 1922 Nobel Prize in Chemistry for his discovery, by means of his mass spectrograph, of isotopes in many non-radioactive elements and for his enunciation of the whole number rule. He was a fellow of the Royal Society and Fellow of Trinity College, Cambridge.

Etymology. Sir derives from the honorific title sire; sire developed alongside the word seigneur, also used to refer to a feudal lord.Both derived from the Vulgar Latin senior, sire comes from the nominative case declension senior and seigneur, the accusative case declension seniōrem.. The form 'Sir' is first documented in English in 1297, as the title of honour of a knight, and latterly a ...