INTRODUCTION. XX111 



as that subject has not already been dealt with, 

 and the doctrine of the tides, and in tracing the 

 course of reasoning by which these important 

 subjects are investigated.* 



The theory of motion in resisting media, and 

 generally whatever relates to fluids, whether their 

 pressure or their movements, forms the next sub 

 ject of inquiry ; but in the elementary view with 

 which we are now occupied, it may be properly 

 passed over, with only this remark, that the 

 matters contained in the Second Book are con 

 veniently described at the end of the account 

 given of the First, although it has been found 

 expedient to follow a different plan of arrange 

 ment in the Analytical View of the Second from 

 that originally laid down. The great progress 

 which has been made in hydrodynamics since the 

 time of Newton, has rendered it necessary to enter 

 more minutely into the investigations connected 

 with the Second Book, than into those of the First 

 and the corresponding portions of the Third. 

 Hence this portion of the present work cannot 

 fail to be found less elementary than the former. 

 An acquaintance with the subject, too, is less 

 indispensable towards obtaining a knowledge of 

 the Newtonian philosophy as exposing the system 



* P. 285. et seq. 

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