THE LAW OF GRAVITATION. 491 



Wc cannot enter uj^on any detail or present even a snmmary of 

 the magnificent result of these labors. They are to be found in his 

 immortal work, the 'Philosophise Naturalis Principia Mathematica/ 

 given to the world in 1687 under the auspices of the Koyal Society. 

 Of this work, the great Laplace, who, of those who have applied the 

 highest powers of the human mind to the investigation of the 

 phenomena of gravitation, stands second only because Newton lived 

 before him, says: "The universality and generality of the discoveries 

 it contains, the number of profound and original views respecting the 

 system of the universe it presents, and all presented with so much 

 elegance, will insure to it a lasting preeminence over all other pro- 

 ductions of the human mind." "It is a work," says Sir David Brewster, 

 ''which will be memorable, not in the annals of one science or one 

 country only, but which will form an epoch in the history of the world, 

 and will ever be regarded as the brightest page in the records of human 

 reason. It is a work which would be read with delight in every planet 

 of our system, and in every system in the universe. There was but one 

 earth on whose form and movements and tides the philosopher could 

 exercise his genius; one moon whose perturbations and inequalities 

 and action he could study ; one sun whose controlling force and appar- 

 ent motions he could calculate and determine; one system of comets 

 whose eccentric paths he could explore and rectify; one universe of 

 stars to whose binary and multiple combinations he could extend the 

 law of gravity. To have been the chosen sage, summoned to the study 

 of that earth, these systems and that universe, the favored lawgiver to 

 worlds unnumbered, the high-priest in the temple of boundless space, 

 was a privilege that could be granted to but one member of the human 

 family; and to have executed the task, was an achievement which, in 

 its magnitude, can be measured only by the infinite in space, and in 

 the duration of its triumphs by the infinite in time." 



