133 



CHAPTER IV. 



DOCTRINE OF ACIDIFICATION AND COMBUSTION. 

 PHLOGISTIC THEORY. 



PUB LIC A TION of the Theory by Beccher and 

 Stahl. It will be recollected that we are 

 tracing the history of the progress only of Che- 

 mistry, not of its errours ; that we are concerned 

 with doctrines only so far as they are true, and 

 have remained part of the received system of che- 

 mical truths. The Phlogistic Theory was deposed 

 and succeeded by the Theory of Oxygen. But this 

 circumstance must not lead us to overlook the 

 really sound and permanent part of the opinions 

 which the founders of the phlogistic theory taught. 

 They brought together, as processes of the same 

 kind, a number of changes which at first appeared 

 to have nothing in common; as acidification, com- 

 bustion, respiration. Now this classification is true; 

 and its importance remains undiminished, whatever 

 are the explanations which we adopt of the pro- 

 cesses themselves. 



The two chemists to whom are to be ascribed 

 the merit of this step, and the establishment of the 

 phlogistic theory which they connected with it, are 

 John Joachim Beccher and George Ernest Stahl; 

 the former of whom was professor at Mentz, and 

 physician to the Elector of Bavaria (born 1625, 



