This Excellent Mathematician having given us, in the Transactions of February last, an account of the cause, which induced him to think upon Reflecting Telescopes, instead of Refracting ones, hath thereupon presented the curious world with an Essay of what may be performed by such Telescopes; by which it is found, that Telescopical Tubes may be considerably shortened without prejudice to their magnifiying effect. On his invention of the catadioptrical telescope, as he communicated to the Royal Society.

Centripetal force is the force by which bodies are drawn from all sides, are impelled, or in any way tend, toward some point as to a center.

What goes up must come down.

Therefore to the same natural effects we must, as far as possible, assign the same causes.

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

Trials are medicines which our gracious and wise Physician prescribes because we need them; and he proportions the frequency and weight of them to what the case requires. Let us trust his skill and thank him for his prescription.

I do not feign hypotheses.