The reason why there were two ways of saying the element aluminum/aluminium has always been one of the those things that made me go "hmmm" But by the same token, it's also always been one of those things that never stuck around in my consciousness long enough for me to look it up. Well, lucky for all us, Michael Quinion over at World Wide Words does an awesome job of going into the lexicon of these words, paying particular attention to why two forms exist - specifically, why the Brits say "Alumininium" and why Americans say "Aluminum." It's actually quite intriguing how it came to be - first starting with Sir Humphry Davy's not being able to make a decision: