Aluminum

Aluminum vs Aluminium
In 1808, British chemist Humphry Davy postulated the existence of a metallic form of alumina ore, which he dubbed alumium. From the Philosophical Transactions of the Royal Society of that year:

"Had I been so fortunate as...to have procured the metallic substances I was in search of, I should have proposed for them the names of silicium, alumium, zirconium, and glucium."

Davy later changed the name to aluminum. He writes in his 1812 Elements of Chemical Philosophy: "As yet Aluminum has not been obtained in a perfectly free state."

Yet that same year, other British chemists settled on the name aluminium, the ending of which they thought was more consistent with the other elements. From the Quarterly Review of 1812:

"Aluminium, for so we shall take the liberty of writing the word, in preference to aluminum, which has a less classical sound." This spelling was the one that caught on in Britain.

In America, however, Davy's original spelling secured a foothold. This probably occurred because Noah Webster favored Davy's spelling of aluminum in his 1828 dictionary, omitting the aluminium spelling. Both spellings were common in 19th century America.

In 1925, the American Chemical Society came down firmly on the side of the aluminum spelling, effectively ending the orthographic debate in America and making the split with British English on this point complete.