As in geometry the most natural way of beginning is from a mathematical point, so is the same method in observations and natural history the most genuine, simple, and instructive.
It is not unlikely, but that there may be yet invented several other helps for the eye, as much exceeding those already found, as those do the bare eye.
The truth is, the science of Nature has been already too long made only a work of the brain and the fancy: It is now high time that it should return to the plainness and soundness of observations on material and obvious things.