Well, you led me into an Internet rabbit hole…
I recall reading that the ‘aluminum’ spelling was a misprint on advertising literature in America by a chemist who had come up with a new process to produce the metal. On reading more, seems that Sir Humphrey David used both variants until settling on the ‘ium’ ending (thus cheering his classical chemistry buddies who always thought that ending was more consistent with other materials, potassium, sodium, magnesium etc):
Then the chemist, Charles Martin Hall, went and used ‘aluminum’ on all his advertising material - even though all his patent filings used the ‘ium’ ending - so maybe typo?
Language - it’s a (mostly) wonderful thing!
