Dr. Bowditch, President of the American Academy. xxix 
numerous perturbations of the motions of the heavenly bodies, he 
has considered only those of the motions of the moon; and the 
most considerable of these, the evection, escaped his investigation. 
He thoroughly established the existence of the principle which he 
had discovered ; but the developement of its consequences and its 
advantages was the work of the successors of this great geometer. 
The imperfections of the calculus of infinites, in its origin, did not 
permit him completely to resolve the difficult problems presented 
by the theory of the system of the world. He was often obliged 
to give mere sketches, or estimates, always uncertain, till they have 
been verified by a rigorous analysis. Notwithstanding these un- 
avoidable defects, however, the importance and general form of 
the discoveries, with numerous profound and original views, 
which were the germ of the most brilliant theories of the geom- 
eters of the last century, — all of which he exhibited with great 
elegance, — ensure to the work on the Mathematical Principles of 
Natural Philosophy, the preéminence over all other productions of 
the human intellect.” * 
Such was the state in which the discoveries of Newton had left 
the science of physical astronomy, when the great work of La 
Place appeared, — undoubtedly the most important one that has 
distinguished the present age; and conducted by an analysis so far 
gradually perfected beyond that of any former period, that it has 
been said by an able writer, that if Newton or Leibnitz should have 
returned to the world at any time since the middle of the last 
century, they would have been unable, without great study, to 
follow the discoveries which their disciples had made, by proceed- 
ing in the line which they themselves had pointed out.t The grand 
* Exposition du Systéme du Monde, p. 418, &c. 
{+ Edinburgh Review, Vol. II. p. 252; in an article by Professor Playfair. 
