It’s a pleasing little reversal of expectations that sodium is actually derived from soda—not the other way round. Soda was already doing the rounds in the fifteenth century as the name for a mysterious alkaline substance, well before sodium was isolated and given its modern name in 1807. The word itself probably comes from the Arabic suwwād, the name of a herb once used in the production of alkaline ashes.
The man who discovered sodium was the indefatigably brilliant Sir Humphry Davy, a chemist of immense flair and literary significance—if only because he became the subject of the very first Clerihew, that most whimsical of poetic forms in which the opening line is invariably someone’s name:
Sir Humphry Davy
Abominated gravy.
He lived in the odium
Of having discovered sodium.
With this, Davy secured both a place in the periodic table and a permanent gig in comic verse. He was also the first Englishman to use the word potassium, derived from potash, the ashy leavings of boiled-down plant matter and another of nature’s curious chemical gifts.
As for soda water, it first fizzes into the written record in 1802, describing plain carbonated water dosed with bicarbonate of soda. To an Englishman, soda still refers exclusively to the fizzy stuff in a siphon, ideally squirted into whisky or over an irritable dinner guest. But to an American, soda is a category: the whole clinking, saccharine menagerie of soft drinks—Cola, Sprite, Dr Pepper, and other bubble-laced potions of childhood.