"I consider it the chief duty of an astronomer to gather the observations of the heavenly bodies, and to explain their motions by hypotheses."

"The order of the planets is as follows: Saturn, Jupiter, Mars, Earth, Venus, Mercury, and in the middle of all, the Sun."

"The earth also is spherical, since it presses upon its center from every direction."

"The universe is a harmonious system, and all its parts are in perfect accord."

"Those things which I am saying now may be obscure, yet they will be made clearer in their proper place."