4 Mr. Colquhoun oh the Life and Writings [Jan. 



dispute, and the number of illustrious names which it enrolled 

 among its disciples. Analogy will suggest to every one that the 

 same phenomena have accompanied each successive revolution 

 in science, or in philosophy, or in religion, froai the dawn of 

 letters in the middle ages down to the present day. 



The radical evd of the ancient system of chemistry, whose 

 baneful influence pervaded every part of it, was Stahl's doctrine 

 ■ of p/ilogibton. When a metal is calcined under contact with the 

 air, it°is gradually converted into an incoherent earthy mass, 

 formerly styled a calx. This calx, according to the old school, 

 is itself a simple substance ; and the metal is a compound of the 

 calx and phlogiston. When a metal, therefore, is calcined, it, 

 in their language, is resolved into the calx, its basis, and at the 

 same time it loses some other thing unknown, — the ideal prin- 

 ciple named phlogiston. To this hypothesis, the processes of 

 experimenting, as they improved, furnished aninsuperable objec- 

 tion. When a metal is converted into a calx, or gets rid of part 

 of its composition, viz, phlogiston, it increases considerably/ in 

 wei<fht ; and, on the contrary, when a calx is brought back to 

 the metallic state, when it gains its phlogistic constituent, it 

 loses precisely the amount of weight 2vhich it had previously gained. 

 That is to say, the simple basis, the calx, is heavier than when 

 to this same basis there is superadded phlogiston. To any 

 unprepossessed mind, this objection is fatal to the hypothesis of 

 Stahl ; but men, bred up in any scientific creed, are not so easily 

 induced to renounce their first belief. And, accordingly, the dis- 

 ciples of Phlogiston only declared that this substance is speciji- 

 cally light, or has a principle of levity; or to speak more clearly, 

 that it paralyses the action of gravity. 



However, the science of chemistry continued to advance, and 

 her busy votaries, in every quarter of Europe, by the ardour of 

 their researches, were every day making new and interesting 

 experiments, the results of which circulated among them with 

 electric rapidity. It is plain that in such a state of things, any 

 theory, which every day put to the test, if radically vicious, must, 

 notwithstanding its weight or prevalence, have its errors at length 

 exposed ; and after a struggle, perhaps severe, be utterly over- 

 thrown, and for ever discarded. Accordingly, whilst every other 

 chemist in Europe, with an obsequiousness unfortunately more 

 to be lamented than wondered at, was perplexing his judgment, 

 and even distorting fact itself, in order to adapt the phlogistic 

 theory to the progress of science, Lavoisier felt it every day 

 more and more impossible to admit its accuracy. The important 

 discoveries of Black, Priestley, Scheele, Cavendish, and others, 

 respecting factitious airs, and the phenomena attendant on the 

 calcination of metals, at an early period seemed to him, not cor- 

 rective but subversive of the system of Stahl. And the process 

 of reasoning by which he gradually arrived at his results is at 



