78 Review of 0. Gregory's Treatise on Mechanics. 



and strictly fluxional, cannot indeed be reduced to the 

 Euclidean method of demonstration so much celebrated ; 

 but a great number of them may be illustrated, if not de- 

 monstrated, on principles depending on the common ge- 

 ometry, or those which are obvious, and universally re- 

 ceived as incontrovertible. This is abundantly manifested 

 by what has been done by Simpson, and the more elegant 

 and profound Maclaurin. These remarks, though applica- 

 ble to the writings of some of the most celebrated modern 

 mathematicians, are more particularly so to those books 

 written apparently more for the purpose of making a pa- 

 rade of science, than affording instruction to readers of the 

 common class. The spirit of ancient times, when difficult 

 arts were intentionally enveloped in mystery, has not 

 wholly evaporated at the present time. Even mathemati- 

 cians appear desirous of gaining celebrity and admiration 

 by unnecessary and most elaborate extensions of the most 

 recondite, and to any besides themselves, the most myste- 

 rious and unintelligible part of their noble and favourite 

 science- How far our author has fallen under this censure, 

 will appear more minutely in the sequel of our review. In 

 the mean while, we wish it to be understood that we have 

 no intention to deprecate his work, but rather are anxious 

 to extend the knowledge of it, and of that branch of science 

 of which it treats, hitherto little cultivated in theory, in 

 this country, by an impartial analysis of that, which we 

 consider, on the whole, as the best, and by far the most 

 profound treatise on the subject, which has appeared in 

 the English language. 



It is not within the compass of our design, to select many 

 portions of this book which are most deserving of praise, 

 or liable to censure. Works of science should be estima* 

 ted by their effect on their ultimate objects, truth and 

 practical utility. We shall, therefore, in our remarks, be 

 confined chiefly to those parts of this production, which in- 

 volve principles, as being by far the most important to the 

 scientific reader. 



In Art. 71, we have this proposition, " If two parallel 

 forces act perpendicularly on a right line in the same di- 

 rection, their resultant is parallel to them, acts in the same 

 direction, is equal to their sum, and divides the line of ap- 

 plication into two parts, which are reciprocally proportion- 



