Newton was a mathematician and arguably the most important scientist in history. I recommend his biography - it's amazing reading.

> I thought Newton was a mathematician, not a scientist.

Newton was a mathematician, scientist, alchemist, theologian (though, by the view of most Christians at the time and now, quite a heterodox one), and high government official that conducted undercover investigations personally. People can sometimes do more than one thing, and Newton did...a lot.