RESEARCHES OF NEWTON’S SUCCESSORS. 3811 
_. Notwithstanding the incomparable sagacity of its author 
the Principia contained merely a rough outline of the 
planetary perturbations. If this sublime sketch did not 
become a complete portrait we must not attribute the 
circumstance to any want of ardour or perseverance ; 
the efforts of the great philosopher were always super- 
human, the questions which he did not solve were inca- 
pable of solution in his time. When the mathematicians 
of the continent entered upon the same career, when 
they wished to establish the Newtonian system upon an 
incontrovertible basis, and to improve the tables of as- 
tronomy, they actually found in their way difficulties 
which the genius of Newton had failed to surmount. 
Five geometers, Clairaut, Euler, D’Alembert, La- 
grange, and Laplace, shared between them the world of 
which Newton had disclosed the existence. They ex- 
plored it in all directions, penetrated into regions which 
had been supposed inaccessible, pointed out there a mul- 
titude of phenomena which observation had not yet de- 
tected; finally, and it is this which constitutes their 
imperishable glory, they reduced under the domain of a 
single principle, a single law, every thing that was most 
refined and mysterious in the celestial movements. Ge- 
ometry had thus the boldness to dispose of the future; 
the evolutions of ages are scrupulously ratifying the 
decisions of science. 
We shall not occupy our attention with the magnifi- 
cent labours of Euler, we shall, on the contrary, present 
the reader with a rapid analysis of the discoveries of his 
four rivals, our countrymen.* 
* It may perhaps be asked why we place Lagrange among the 
French geometers? This is our reply : It appears to us that the indi- 
vidual who was named Lagrange Tournier, two of the most character- 
