Mr. G. F. Rodwell on the Theory of Phlogiston. 23 



simplicity and intelligibility) ; but he has stated in writing that 

 such is the composition of the bodies specified ; we do not know 

 by what means he arrived at such conclusions. I may allude 

 en passant to the very apparent inception of the idea of chemical 

 affinity in the writings of Becher. One substance " attrahet " 

 another, in virtue of its " affinitas;" "reactio" ensues; he per- 

 tinently remarks that the stronger the " subjecta reagentia, hoc 

 fortior etiam est reactio, et reactionis effectus." 



The term phlogiston appears to have been solely used by Be- 

 cher in the sense mentioned above, viz. as an adjective; he did not 

 use it as a substantive, he did not designate the matter or prin- 

 ciple of fire by it ; indeed he remarks in the Physica Subterranea 

 that materia ignis is well called " salamandra/ } because it feeds 

 upon fire. Moreover Stahl in the Specimen Becherianum writes, 

 " Materia et principium ignis, non ipse ignis, ego Phlogiston ap- 

 pellare coepi ; " and it is curious, as indicating the transition, 

 that in his earlier works the word is used as an adjective : thus 

 in the Zymotechnia Fundamentalist published in 1697, I find 

 the word " §Xo<yi(jiaTov" 



Becher diligently consulted the works of former and contem- 

 porary chemists ; I do not remember to have met with any pre- 

 vious writer who so constantly quotes the opinions of others, 

 and who so persistently endeavours to support his own opinions 

 by those of his predecessors. He was thoroughly versed in che- 

 mical literature; if this had not been the case, he could not have 

 commenced that plan of systematization which was so extensively 

 carried out by Stahl. As the facts of a science accumulate, ge- 

 neralization becomes a necessity ; and this is usually effected by 

 means of a theory. In the time of Becher a vast number of 

 chemical facts were known, but they were the disconnected links 

 of a chain, and were loosely scattered about ; Becher laudably 

 attempted to introduce order among them. He did not accom- 

 plish this ; but the more comprehensive (and less original) mind 

 of his disciple Stahl, taking his design as the starting-point, did 

 accomplish it. 



Stahl converted Becher' s (pXoytaTov into a substantive, and 

 applied it to designate the materia ignis so often spoken of in 

 the works of former writers on chemistry ; and at the same time 

 he endued it with certain extended functions, many borrowed 

 from Descartes, some added by himself. 



George Ernest Stahl was born at Anspach, in 1660. He pur- 

 sued his studies in the University of Jena, and made such pro- 

 gress in medicine that in 1694 he was appointed second Profes- 

 sor of Medicine in the recently founded University of Halle, 

 which appointment he held for twenty- two years. In 1716 he 

 was appointed physician to the King of Prussia, and he then re- 



