Pictures, propagated by motion along the fibers of the optic nerves in the brain, are the cause of vision.

...from the same principles, I now demonstrate the frame of the System of the World.

If two angels were sent down from heaven -one to conduct an empire and the other to sweep the streets -they would feel no inclination to change employment because an angel would know that no matter what we are doing, it's an opportunity to bring joy, deepen our understanding and expand our life.

It seems probable to me that God, in the beginning, formed matter in solid, massy, hard, impenetrable, moveable particles, of such sizes and figures, and with such other properties, and in such proportions to space, as most conduced to the end for which He formed them; and that these primitive particles, being solids, are incomparably harder than any porous bodies compounded of them, even so very hard as never to wear or break in pieces; no ordinary power being able to divide what God had made one in the first creation.

Where both are friends, it is right to prefer truth.

If I am anything, which I highly doubt, I have made myself so by hard work.

To me there has never been a higher source of earthly honor or distinction than that connected with advances in science.