448 Mr, Dames on Flame, [Dec; 



operation are known, from other experiments, to be in opposite 

 states of electricity ; and, 2. Flame gives, under some circum- 

 stances, indications that electricity is developed during the 

 changes which inflammation produces. 



Respecting the nature of flame there are two opinions. The 

 first is that of Mr. Sym, who has, in the eighth volume of the 

 Annals of' Fhilosophj/y attempted to show, that flame is capable 

 of being truncated, and that it presents only a superficial 

 process of combustion. The other opinion is that of SirH. 

 Davy, who conceives that " flame cannot be regarded as a 

 mere combustion at the surface of contact of the inflammable 

 matter." 



These opinions are manifestly at variance with each other. 

 I shall request your attention to a brief examination of the 

 subject. 



Mr. Sym in his paper, the merits of which have been most 

 unaccountably overlooked, has described some very amusing 

 and easy experiments in illustration of his opinion. " When a 

 wire gauze of the requisite fineness is held horizontally across 

 the flame of a candle, the appearance is not that of repression, 

 but of truncation. The part of the flame below the gauze has 

 suffered no alteration in shape, size, or intensity ; and the part 

 which ought to be above has simply disappeared. In looking 

 down, therefore, through the gauze into a flame thus truncated, 

 we have an opportunity of examining a transverse section of 

 it, and of thus inspecting its inside. Now it is immediately 

 perceived that this transverse section consists of a narrow 

 himinous ring surrounding a disk which is not luminous ; and 

 though the obscurity of the disk may at first sight be ascribed 

 to the blackness of the wick, seen through intervening flame, 

 it will be discovered, on more careful examination, that the wick 

 occupies only the centre of the obscure space, which extends to 

 some distance around it." Mr. Sym therefore contends, that 

 *^ the only conclusion that remains, or rather the direct percep- 

 tion, is, that the lower segment of the apparent flame of a 

 candle consists of only a thin superficial film of real flame, 

 which has the shape of a cup, surrounding the wick, and 

 closing in upon it below, but filled, beside, with volatilized 

 wax." 



Mr. Sym" has given some interesting modifications of his 

 experiments. What I have extracted is, however, sufficient 

 for our present purpose. Those who desire more information 

 on the subject would be gratified by consulting the paper re- 

 ferred to. 



Sir H. Davy states, in page 46 of his Researches, that " the 

 flame of combustible bodies may in all cases be considered as 

 the combustion of an explosive mixture of inflammable gas, or 

 vapour, with air. It cannot be regarded as a mere combustion. 



