DES CARTES. 



substance. The essence of matterbeing 

 thus fixed in extension, Des Cartes con- 

 cludes that there is no vacuum, nor any 

 possibility of it in nature, but that the 

 universe is absolutely full : by this princi- 

 ple, mere space is quite excluded ; for 

 extension being implied in the idea of 

 space, matter is so too. 



Des Cartes defines motion to be the 

 translation of a body from the neighbour- 

 hood of others that are in contact with 

 it, and considered as at rest, to the neigh- 

 bourhood of other bodies ; by which he 

 destroys the distinction between motion 

 that is absolute or real, and that which 

 is relative or apparent. He maintains,that 

 the same quantity of motion is always 

 preserved in the universe, because God 

 must be supposed to act in the most 

 constant and immutable manner : and 

 hence also he deduces his three laws of 

 motion. 



Upon these principles Des Cartes ex- 

 plains mechanically how the world was 

 formed, and how the present phenomena 

 of nature came to arise. He supposes 

 that God created matter of an indefinite 

 extension, which he separated into small 

 square portions or masses, full of angles ; 

 that he impressed two motions on this 

 matter ; the one, by which each part re- 

 volved about its own centre; and another, 

 by which an assemblage or system of 

 them turned round a common centre. 

 From whence arose as many different vor- 

 tices, or eddies, as there were different 

 masses of matter thus moving about com- 

 mon centres. 



The consequence of these motions in 

 each vortex, according to Des Cartes, is 

 as follows : the parts of matter could not 

 thus move and revolve amongst one ano- 

 ther, without having their angles gradual- 

 ly broken : and this continual friction of 

 parts and angles must produce three ele- 

 ments : the first of these, an infinitely fine 

 dust formed of the angles broken off; the 

 second, the spheres remaining, after all 

 the angular parts are thus removed ; and 

 those particles not yet rendered smooth 

 and spherical, but still retaining some of 

 their angles, and hamous parts, form the 

 third element. 



Now the first or subtilest element, ac- 

 cording to the laws of motion, must oc- 

 cupy the centre of each system, or vortex, 

 by reason of the smallness of its parts ; 

 and this is the matter which constitutes 

 the sun and the fixed stars above, and tfee 

 fire below. The second element, made 

 up of spheres, forms the atmosphere, 

 and all the matter between the earth and 



the fixed stars : in such sort, that the 

 largest spheres are always next the cir- 

 cumference of the vortex, and the small- 

 est next its centre. The third element, 

 formed of the irregular particles, is the 

 matter that composes the earth, and all 

 terrestrial bodies, together with comets, 

 spots in the sun, &c. 



He accounts for the gravity of terres- 

 trial bodies from the centrifugal force of 

 the ether revolving round the earth: and 

 upon the same general principles he pre- 

 tends to explain the phenomena of the 

 magnet, and to account for all the other 

 operations in nature. 



Of this great man many eulogia have 

 been published, by persons very capable 

 of appreciating his worth and his talents. 

 We shall mention the opinion entertained 

 of him by two orthee of our own coun- 

 trymen. 



Dr. Barrow, in his " Opuscula," ob- 

 serves, that Des Cartes was doubtless a 

 very ingenious man, and a real philoso- 

 pher, and one who seems to have brought 

 those assistances to that part of philoso- 

 phy relating to matter and motion, which 

 perhaps no one had done before; namely, 

 a great skill in mathematics ; a mind ha- 

 bituated, both by nature and custom, to 

 profound meditation; a judgment exempt 

 from all prejudices and popular errors, 

 and furnished with a good number of cer- 

 tain und select experiments; a great deal 

 of leisure ; an entire disengagement, by 

 his own choice, from the reading of use- 

 less books,and the avocations of life: with 

 an incomparable acuteness of wit, and an 

 excellent talent of thinking clearly and 

 distinctly, and of expressing his thoughts 

 with the utmost perspicuity. 



Dr. Halley, in a paper concerning op- 

 tics, affirms that Des Cartes was the first, 

 who, in modern times, discovered the 

 laws of refraction, and brought dioptrics 

 to a science. And Dr. Keil says, that 

 Des Cartes was so far from applying geo- 

 metry and observations to natural philo- 

 sophy, that his whole system is but one 

 continued blunder, on account of his ne- 

 gligence in that point ; which he could 

 easily prove, by showing that his theory 

 of the vortices, upon which his system is 

 founded, is absolutely false, for that New- 

 ton has shewn that the periodical times 

 of all bodies that swim in vortices must 

 be directly as the squares of their dis- 

 tances fi'om the centre of them ; but it 

 is evident, from observations, that the 

 planets, in moving round the sun, ob- 

 serve a law quite different from this ; for 

 the squares of their periodical times are 



