IET. Vis.

AND DISCOVERIES.

•I 17

iad be-vation.oon isifirmedry im-in the1 from

that af force3 calledistance.e pettynade ited thee ; but:h, andfile, he:artli inie earth

in this

novinglites ofstanets;

exactly

fluencet force,ton hasived of

the

the impuse by which she has a tendency to movein a right line from west to east, and the centralforce only remained, she would fall towards ourglobe, and describe fifteen Paris feet in the firstminute of her descent. And as the mean dis-tance of the moon from the earth is sixty of theearth’s femi-diameters, and the force of gravityincreases in proportion as the squares of thedistances from the center decrease, the gravityof the moon, near the surface of the earth,would, therefore, be the square of 60, or 3600times greater than at her present mean distance ;so that, in this situation, slie would describe3600 times fifteen feet in a minute.

Now, as it was demonstrated by Galileo, thatfalling bodies move through spaces which areproportional to the squares of the times in whichthey are described, it follows, that the moon,which, at a small distance from the earth, wouldhave described 3600 times fifteen feet in oneminute, must have described fifteen feet in thefirst sixtieth part of that minute, or in the firstsecond. And as we know likewise, from ex-periment, that all heavy bodies, near the earth’ssurface, fall fifteen Paris feet in the first secondof their descent, it is plain that they must beacted upon by gravity in the fame manner as themoon, and that both of them are governed byshe fame laws; for so exact; a conformity, orJ 3 rather