Newton discovered the binomial theorem, calculus, the laws of motion, universal gravitation, and the decomposition of light. Any of these discoveries would have made him famous forever. But instead we got all of this from just one man. And all of this before he reached the age of 40.
After this he left teaching at Cambridge and moved to London to become head of the Royal Mint. Perhaps that is why he started his study of alchemy. Alchemy was state of the art at that time. Newton was trying to turn lead into gold. Of course we know today that it is theoretically possible to change lead into gold by changing the number of protons in the nucleus of an atom, but the process would be prohibitively expensive. It is much cheaper to dig gold out of the ground.
Mathematics and classical physics got so much from this one man. Must we demand that he invent modern chemistry as well?
Newton has my vote for the greatest scientific genius in history. I recently saw a poll in which Newton received the most votes of modern scientists for that honor. However, I think Dawkin's proposal to substitute Newton's birthday for Christmas is very silly. But then atheists do often say very silly things.
Please don't misunderstand me, I'm not trying to diminish his accomplishments in the slightest. I was just speculating that had he not drifted off into studies of theology and the occult he may well have produced even more substantive work. As it is, I quite agree that he's the greatest scientist of all time.