EPOCH OF THE THEOKY OF OXYGEN. 277 



all that was discovered concerning the composition of alec hoi, oil, ani- 

 mal and vegetable substances, and many other bodies. 



It is not necessary for us to consider any further the evidence for 

 this theory, but we must record a few circumstances respecting its 

 earlier history. Key, a French physician, had in 1630, published a 

 book, in which he inquires into the grounds of the increase of the 

 weight of metals by calcination. 3 He says, " To this question, then, 

 supported on the grounds already mentioned, I answer, and maintain 

 with confidence, that the increase of weight arises from the air, which 

 is condensed, rendered heavy and adhesive, by the heat of the furnace." 

 Hooke and Mayow had entertained the opinion that the air contains 

 a " nitrous spirit," which is the supporter of combustion. But Lavoi- 

 sier disclaimed the charge of having derived anything from these 

 sources ; nor is it difficult to understand how the received generali- 

 zations of the phlogistic theory had thrown all such narrower explana 

 tions into obscurity. The merit of Lavoisier consisted in his combin- 

 ing the generality of Stahl with the verified conjectures of Rey and 

 Mayow. 



Xo one could have a better claim, by his early enthusiasm for 

 science, his extensive knowledge, and his zealous labors, to hope 

 that a great discovery might fall to his share, than Lavoisier. His 

 father, 4 a man of considerable fortune, had allowed him to make 

 science his only profession ; and the zealous philosopher collected 

 about him a number of the most active physical inquirers of his time, 

 who met and experimented at his house one day in the week. In this 

 school, the new chemistry was gradually formed. A few years after 

 the publication of Priestley's first experiments, Lavoisier was struck 

 with the presentiment of the theory which he was afterwards to pro- 

 duce. In 1772, he deposited 6 with the secretary of the Academy, a 

 note which contained the germ of his future doctrines. " At that 

 time," he says, in explaining this step, "there was a kind of rivaln 

 between France and England in science, which gave importance to 

 new experiments, and which sometimes was the cause that the writers 

 of the one or other of the nations disputed the discovery with the real 

 author." In 1777, the editor of the Memoirs of the Academy speaks 

 of his theory as overturning that of Stahl ; but the general acceptance 

 of the new opinion did not take place till /ater. 



3 Thomson, Hist. Chem, ii. 95. ' Biorjr. Univ. (Cuvier.) 



5 Thomson, ii. 99. 



