[5] Newton laid the foundations of Celestial Mechanics, at the close of the seventeenth century, by the discovery of the principle of universal gravitation.

Even in his own hands, this discovery led to important consequences, but it has required a century and a half, and a regular succession of intellects the most powerful, to fill up the outline sketched by him.

In this last named work, the illustrious author has proposed to himself his object, to unite all the theories scattered throughout the various channels of publication, employed by his predecessors, to reduce them to one common method, and present them all in the same point of view.

[6]If one were asked to name the two most important works in the progress of mathematics and physics, the answer would undoubtedly be, the Principia of Newton and the Mécanique Céleste of Laplace.

The Principia gives the plans and specifications of the foundations; the Mécanique Céleste affords the key to the vast and complex superstructure.

[13]In 1826, it was still felt by Henry Brougham, president of the Society for the Diffusion of Useful Knowledge, that the British reader was lacking a readable translation of Mécanique Céleste.

He thus approached Mary Somerville, who began to prepare a translation which would "explain to the unlearned the sort of thing it is - the plan, the vast merit, the wonderful truths unfolded or methodized - and the calculus by which all this is accomplished".