INTRODUCTION.

My principal aim, in the inquiry I am about to undertake, is to give myself — and perhaps a few readers — clear ideas of those primitive laws of nature that Newton discovered.

I shall examine how far philosophers had gone before him, where he began, where he stopped, and sometimes what has been discovered even after him.

I shall begin with light, which he alone truly understood; I shall end with the examination of gravity, and of that general law of gravitation or attraction — the universal spring of nature — a discovery for which we owe thanks to him alone.

We will attempt to present these Elements in a way that is accessible to those who know only the name of Newton and of philosophy.

The science of nature is a wealth that belongs to all mankind.

All would like to have knowledge of their inheritance; few have the time or patience to calculate it.

Newton calculated for them.

Here, we must sometimes be content with the sum of those calculations.

Every day, a public man — a minister — forms a sound idea of the result of operations that he himself could not carry out; other eyes have seen for him, other hands have worked, and have put him, through a faithful account, in a position to make his judgment.

Every thinking person will be almost in the position of such a minister.