 While still on the island, Darwin was inspired to think of writing a book on geology, and later wrote of "seeing a thing never seen by Lyell, one yet saw it partially through his eyes".Customarily the ship's surgeon took the position of naturalist, and "Beagle"'s surgeon Robert McCormick sought fame and fortune as an explorer.When they first met at the start of the voyage, Darwin had commented that "My friend [McCormick] is an ass, but we jog on very amicably".