Write your own Book of Nature in this Naturalists’ Journal; a guide to an exhibit held at the Amer. Philosophical Soc. Take your own naturalist’s expedition inside the museum . . . & outside! Pickled fish, dried plants, colorful drawings, old books in glass cases: Many of the things in this natural history exhibition were collected in the years between 1730 & 1860, as evidence of the incredible variety of life that exists -- or once existed -- on earth. The people who collected these amazing things are called naturalists. A naturalist is a lot like a detective. These naturalists were trying to solve big mysteries about the natural world around them, such as: Why does a rattlesnake have a rattle? How did seashells get on top of a mountain far from the ocean? Illus.