THE REVIVED THEORY OF PHLOGISTON. 561 



Fourcroy next gave in his adhesion ; and soon afterward De Morveau, 

 invited to Paris expressly to be reasoned with by Lavoisier, succumbed 

 to the reasons set before him. The four chemists then associated 

 themselves together, and, in spite of a strong though short-lived op- 

 position both in England and Germany, succeeded in obtaining for La 

 Chlmie Frangaise an all but universal recognition. 



The principal articles of the new or antiphlogistic theory of com- 

 bustion propounded by Lavoisier are as follows : That combustible 

 bodies in burning yield products of various kinds, solid in the case of 

 phosphorus and the metals, liquid in the case of hydrogen, gaseous in 

 the case of cai - bon and sulphur. That in every case the weight of the 

 products formed by the burning is greater than the weight of the 

 combustible burned. That the increase of weight is due to an addition 

 of matter furnished to the combustible by the air in which its burning 

 takes place. That bodies of which the weights are made up of the 

 weights of two or more distinct kinds of matter are of necessity com- 

 pound ; whereas bodies of which the weights cannot be shown to be 

 made up of the weights of two or more distinct kinds of matter are in 

 effect simple or elementary. That, inasmuch as the weights of the 

 products furnished by the burning of different combustibles are made 

 up of the weights of the combustible burned and of the oxygen con- 

 sumed in the burning, these products are compound bodies oxides in 

 fact of the substances burned. That, inasmuch as given weights of 

 many combustibles, as of hydrogen, sulphur, phosphorus, carbon, and 

 the metals, are not apparently made up of the weights of two or more 

 distinct kinds of matter, these particular combustibles are in effect 

 elementary ; as for the same reason is the oxygen with which in the 

 act of burning they enter into combination. And, lastly, that com- 

 bustion or burning consists in nothing else than in the union of com- 

 bustible matter, simple or compound, with the empyreal matter, oxygen 

 the act of union being somehow attended by an evolution of light 

 and heat. And, except that it would be necessary nowadays to ex- 

 plain how, in certain cases of combustion, the combustible enters into 

 union not with oxygen, but with some analogue of oxygen, the above 

 precise statement might equally well have been made by Lavoisier in 

 1785, or be made by one of ourselves at the present day. 



Lavoisier's theory of combustion being known as the antiphlogistic 

 theory, the question arises, What was the phlogistic theory to which 

 it was opposed, and which it succeeded so completely in displacing ? 

 This phlogistic theory was founded and elaborated at the close of the 

 seventeenth century by two German physicians, Beccher and Stahl. 

 Having exercised a scarcely-disputed authority over men's minds 

 until the notorious defection in 1785, it preserved for some years 

 longer a resolute though tortuous existence, and was to the last de- 

 fended and approved by our own Priestley and Cavendish who died, 

 the former in 1804, and the latter in 1810. 



VOL. IX. 36 



