236 



LECTURE XX. 



ON THE HISTORY OF MECHANICS. 



J- HE order which we have pursued, in considering the various departments 

 of mechanical science, has been in great measure synthetical, dictated by 

 the plan of proceeding logically from the most simple principles to their more 

 complicated combinations, so as to build at every step on foundations which 

 had been firmly laid before: and this method is unquestionably the best 

 adapted for the expeditious progress of a student in sciences with which he 

 is unacquainted. But having once acquired a certain degree of knowledge, 

 he is anxious to be informed by what steps that knowledge w.is originally 

 obtained, and to what individuals mankind is indebted for each improvement 

 that has been successively made. Hence, although we cannot attempt to 

 enter into a complete history of mechanics, it may still be satisfactory to 

 take a short retrospect of a few of the most remarkable eras in mechanical 

 philosophy, and in those parts of mathematics on which it immediately 

 depends. 



It is universally allowed that the Greeks derived the elements of mathema- 

 tical, mechanical, and astronpmical learning from Egypt and from the East. 

 Diogenes Laertius, who appears to be very desirous of claiming, for his 

 countrymen, the merit of originality, does not deny that Thales and Pytha- 

 goras acquired much of their knowledge in their travels. Thales of Miletus 

 is the first that can be supposed to have introduced these studies into Greece. 

 Moeris, who was probably a king of Egypt, and Theuth or Thoth, a native 

 of the same country, are mentioned as having laid the foundations of geome- 

 try; but the science could scarcely have extended, in those ages, further than 

 was barely necessary for the measurement of land: since Thales, or even a 

 later philosopher, is said to have first discovered that two lines drawn from 



