18 Life and Character of Nathaniel Bowditch. 



ticians have since that epoch, succeeded in reducing to this great 

 law of nature all the known phenomena of the system of the 

 world, and have thus given to the theories of the heavenly bod- 

 ies and to astronomical tables, an unexpected degree of precision. 

 My object is to present a connected view of these theories, which 

 are now scattered in a great number of works. The whole of the 

 results of gravitation, upon the equilibrium and motions of the 

 fluid and solid bodies, which compose the solar system, and the 

 similar systems, existing in the immensity of space, constitute the 

 object of Celestial Mechanics^ or the application of the principles 

 of mechanics to the motions and figures of the heavenly bodies. 

 Astronomy, considered in the most general manner, is a great prob- 

 lem of mechanics, in which the elements of the motions are the 

 arbitrary constant quantities. The solution of this problem de- 

 pends, at the same time, upon the accuracy of the observations, 

 and upon the perfection of the analysis. It is very important to 

 reject every empirical process, and to complete the analysis, so 

 that it shall not be necessary to derive from observations any but 

 indispensable data. The intention of this work is to obtain, as 

 much as may be in my power, this interesting result." 



It is a work of great genius and immense depth, and exceed- 

 ingly difficult to be comprehended. This arises not merely from 

 the intrinsic difficulty of the subject, and the medium of proof 

 employed being the higher branches of the mathematics, — but 

 chiefly from the circumstance that the author, taking it for granted 

 that the subject would be as plain and easy to others as to himself, 

 very often omits the intermediate steps and connecting links in 

 his demonstrations. He jumps over the interval, and grasps the 

 conclusion as by intuition. Dr. Bowditch used to say, " I never 

 come across one of La Place's ' Thus it plainly appears,' without 

 feeling sure that I have got hours of hard study before me to fill 

 up the chasm, and find out and show how it plainly appears." 



Dr. Bowditch says, in his Introduction to the first volume, " The 

 olDJect of the author, in composing this work, as stated by him in 

 his Preface, was to reduce all the known phenomena of the sys- 

 tem of the world to the law of gravity, by strict mathematical 

 principles ; and to complete the investigations of the motions of 

 the planets, satellites, and comets, begun by Newton in his Prin- 

 cipia. This he has accomplished, in a manner deserving the 

 highest praise, for its symmetry and completeness ; but from the 



