48 Mechanical PhllosopJijj. [Chap. I. 



calculation, as from a laborious comparison of 

 facts. It furnishes most important information to 

 the cnc^ineer ; and enables liim now to resolve, with 

 sufficient precision, many questions, in answer ta 

 which little ])ut conjecture, and that too often most 

 mischievously wide of the truth, could be offered 

 before. In short, the gCxieral proposition, deduced 

 from the chevalier's numerous facts and experi- 

 ments, respecting the motion of fluids, has been 

 pronounced one of the most valuable results of mo- 

 dern inquiry *. 



Much light has been thrown, during the last 

 century, on the doctrine of Tides. Newton was 

 the first who gave a satisfactory explanation of this 

 subject. He showed that the tides are caused by 

 the attraction of the sun and moon, and laid down 

 some of the general laws of this attraction. But 

 it has been remarked, that the wide steps taken by 

 this philosopher, in his investigation, left ordinary 

 minds frequently at a loss ; and that many of his 

 principles require very great mathematical know- 

 ledge to satisfy us of their truth. Accordingly the 

 Academy of Sciences at Paris, soon after the death 

 of the illustrious Briton, wishing to have this as 

 well as some other parts of philosophy exhibited 

 in a satisfactory, and, as far as could be, in a popu- 

 lar manner, published a prize question relative to 

 the tides. This produced three excellent disserta- 

 tions on the subject, by Mr. Maclaurin, D. Ber- 

 noulli, and Euler. Of these the work of Bernoulli 

 is considered the best, and is, perhaps, the most 



^ See Emyclopa:dia, Art. Water-Works^ 



