�y��vlog

In this work, the Mécanique Analytique, Lagrange develops an equation from which it can be proved conclusively that to explain any group of phenomena measured by energy an infinite number of hypotheses may be employed.

This was proved158 by Lagrange in the Mécanique Analytique as a generalisation of a theorem given by Euler for a rigid body set into rotation by an impulse.

The originality and suggestiveness of this part of the book, taken alone, would entitle it to rank with the great classics—the Mécanique Céleste, the Mécanique Analytique, and the memoirs of Jacobi and Hamilton—all of which were an outcome of the Principia, and from which, with the Principia, the authors of the Natural Philosophy drew their inspiration.

But William had just begun to study Fourier's famous book, La Théorie Analytique de la Chaleur, and took it with him.

Two other great works of his father's collection of mathematical books, Laplace's Mécanique Céleste and Lagrange's Mécanique Analytique, seem also to have been read about this time, and to have made a deep impression on the mind of the youthful philosopher.