148 HISTORY OF SCIENCE. 



the first professors in the institution, which, about the beginning of 

 the seventeenth century, was founded by a wealthy London merchant 

 named Gresham as a college of science. The Gresham College could 

 for several generations boast of having some of the greatest men of 

 science of the day for its professors ; but subsequently the institution 

 lapsed into obscurity, and its emoluments were pocketed by persons 

 who were contented to repeat a merely formal discourse, which until 

 within the last few years was delivered only in the Latin language, and 

 for which it was difficult to obtain any auditors at all ! 



Passing over many names and many discoveries of mathematical 

 science, of which the plan of the present work will hardly admit space 

 for the mere mention, although they belong to the history of mathe- 

 matics, we may now proceed to another of the most important steps 

 by which that science advanced during the seventeenth century ; and 

 in doing so we come to one of those great names which form the land- 

 marks, as it were, of the intellectual progress of mankind. RENE 

 DESCARTES was born at La Haye in Touraine in 1596, and at an early 

 age showed great aptitude in various departments of science and litera- 

 ture. He passed through the usual course of instruction in the Jesuit's 

 College at La Fleche, and he then adopted the profession of arms \ 

 and first as a soldier and afterwards as a student he visited in turn 

 nearly every country in Europe, Spain and Portugal being perhaps the 

 only exceptions. He pursued with eagerness a great variety of different 

 studies, including mathematics, physics, metaphysics, anatomy, and 

 physiology. His fame now rests mainly upon his philosophical works 

 and upon the great inventions in geometry which he first announced 

 to the world in a work published in Holland in 1637. 



Descartes' philosophy, of which we may here say a few words before 

 relating his mathematical inventions, concurred with Bacon's in de- 

 stroying the previous systems which relied upon authority. But while 

 Bacon proposed to discover truths for himself by inductive reasoning 

 founded on experiences of the external world, Descartes' path to truth 

 was by deductive reasoning from his own internal consciousness. The 

 fundamental rule and criterion of truth which Descartes immediately 

 deduces from his celebrated first principle, " I think, and therefore T 

 exist" is that "the things which we conceive very clearly and very 

 distinctly are all true ; " only, he naively remarks, there is some diffi- 

 culty in observing which are the things that we do conceive clearly. 

 Descartes, by making deduction the great instrument for his search 

 after truth, was, in a sense, the complement of Bacon ; and again, 

 while the former loved mathematics, and placed that science in the 

 first rank, the latter disliked it and considered it as merely the hand- 

 maid of physical science. Descartes agreed with Bacon in rejecting 

 authority. Pie teaches that if you wish to discover truth, you must 

 train your mind to form correct judgments : the rules he gives to this 

 end being that the intellect must be exercised only on those matters 



