THE CHEMICAL ELEMENTS. 733 



THE CHEMICAL ELEMENTS: 



HISTORY OF THE CONCEPTION WHICH THIS TERM INVOLVES. 



Br JOSIAH PAKSONS COOKE, LL. D., 



KEYING PEOFESSOK OF CHEMISTEY AND MINEEALOGT \S HAEVARD UNIVEESITr. 



THE intellectual force of Aristotle ruled in cliemistry even 

 longer than in other departments of physical science. In 

 mechanics and astronomy the dogmas of Aristotle were effectually 

 laid by Galileo early in the seventeenth century ; but his doctrine 

 of the four elements* — in one form or other — was accepted in 

 chemistry to the close of the eighteenth century. The wonderful 

 history of the philosophy of the great Stagirite — a philosophy 

 which ruled the intellectual world in physics as well as in meta- 

 physics for more than twenty centuries — is constantly referred to 

 as an illustration of the vices of speculative thought when not 

 based on experimental evidences ; and, undoubtedly, the aberra- 

 tions of many of his later disciples justify this opinion. Among 

 these Kepler is especially consi^icuous, for he, by applying the 

 doctrines in a most grotesque and absurd manner, did not a little to 

 bring Aristotle's philosophy of mechanics into contempt. Never- 

 theless, Aristotle himself was for his time an acute observer, as 

 his writings abundantly indicate ; and his philosophical views are 

 brought forward rather to justify his conclusions than as the 

 basis of his inferences. So it is with the doctrine of the four ele- 

 ments. Earth, water, air, and fire were obviously to him the 

 essences, or, to use a later and more descriptive word, the " sub- 

 stantia " of four conditions of matter. Three of these we recog- 

 nize as clearly as he did ; and the fourth, fire, which he regarded 

 as a more sublimated condition than air, and thought he actually 

 saw in the upward motion of flames, has its modern representative 

 in Mr. Crookes's fourth condition of matter. 



Since Aristotle regarded motion as an attribute of inanimate 

 as well as of living bodies— a stone falling for the same reason 

 that a fish swims— and as he noticed that while water and stones 

 tend to fall, flame and air tend to rise, he regarded the last as 

 having a natural motion upward, and the first as having a natural 

 motion downward ; and thus to him specific levity seemed as much 

 a direct inference of observation as specific gravity. By this inher- 

 ent motion the four elements appeared to strive to separate, and 

 each to tend to its own place — fire taking the highest place, air the 



* The doctrine of the four elements, although usually associated with Aristotle, is really 

 as old as Greek philosophy, and can certainly be traced back to Empedoclcs, who lived in 

 the second third of the fifth century before Christ — that is, a century before the time of 

 Aristotle. 



