564 THE POPULAR SCIENCE MONTHLY. 



them, and capable of being transferred from the combustible body 

 which has it to an incombustible body which has it not, rendering the 

 body that was energetic and combustible inert and incombustible, and 

 the body that was inert and incombustible energetic and combustible, 

 and further rendering some particular body combustible over and over 

 again. That this is a fair representation of the views held by phlo- 

 gistic chemists is readily recognizable by a study of chemical works 

 written before the outbreak of the antiphlogistic revolution. After 

 Lavoisier's challenge, the advocates of phlogiston, striving to make it 

 account for a novel order of facts with which it had little or nothing 

 to do, were driven to the most incongruous of positions ; for, while 

 Priestley wrote of inert nitrogen as phlogisticated air, Kirwan and 

 others regarded inflammable hydrogen as being phlogiston itself in 

 the isolated state. Very different is the view of phlogiston to be 

 gathered from the writings of Dr. Watson, for example, who was ap- 

 pointed Professor of Chemistry at Cambridge in 1764, became Regius 

 Professor of Divinity in 1771, and Bishop of Llandaff in 1782. This 

 cultivated divine, indifferent, it is true, to the novel questions by which 

 in less placid regions men's minds were so deeply stirred, amused the 

 leisure of his dignified university life by writing scholarly accounts 

 of the chemistry it had formerly been his province to teach ; and in 

 the first volume of his well-known " Chemical Essays," published in 

 1781, the following excellent account of phlogiston is to be found : 



" Notwithstanding all that perhaps can be said upon this subject, I am sensi- 

 ble the reader will be still ready to ask, What is phlogiston ? You do not surely 

 expect that chemistry should be able to present you with a handful of phlogis- 

 ton, separated from an inflammable body; you may just as reasonably demand 

 a handful of magnetism, gravity, or electricity, to be extracted from a magnetic, 

 weighty, or electric body. There are powers in Nature which cannot otherwise 

 become the objects of sense than by the effects they produce ; and of this kind 

 is phlogiston. But the following experiments will tend to render this perplexed 

 subject somewhat more clear : 



" If you take a piece of sulphur and set it on fire it will burn entirely away, 

 without leaving any ashes or yielding any soot. During the burning of the 

 sulphur a copious vapor, powerfully affecting the organs of sight and smell, is 

 dispersed. Means have been invented for collecting this vapor, and it is found 

 to be a very strong acid. The acid thus procured from the burning of sulphur 

 is incapable of being either burned by itself or of contributing toward the sup- 

 port of fire in other bodies ; the sulphur, from which it was procured, was 

 capable of both : there is a remarkable difference, then, between the acid pro- 

 cured from the sulphur and the sulphur itself. The acid cannot be the only 

 constituent part of sulphur; it is evident that something else must have entered 

 into its composition, by which it was rendered capable of combustion. This 

 something is, from its most remarkable property, that of rendering a body com- 

 bustible, properly enough denominated the food of fire, the inflammable prin- 

 ciple, the phlogiston. . . . This inflammable principle or phlogiston is not one 

 thing in animals, another in vegetables, another in minerals; it is absolutely the 

 same in them all. This identity of phlogiston may be proved from a variety 



