^84 Mr Blackadder on the Constitution of Flame, 



are only cells which have not been filled with calcareous mat- 

 ter, and that the supposed ova are the usual granular mat- 

 ter of the cellular substance. — 'Commumcaiion froin Dr Grant, 



On the Constitution of Flame. By H. Home Blackadd^k, 

 Esq. F. R. S. E. (Communicated by the Author.) 



Jt-iVEN at the present day, the constitution of an ordinary 

 flame would seem to be but very imperfectly understood ; at 

 least the following notice, of a very recent date, would naturally 

 lead to such a conclusion. " It appears, from a series of expe- 

 riments by Mr Davies of Manchester, that there is considerable 

 foundation for the opinion of Mr Sym, that the flame of a can- 

 dle is a conical surface, the interior of which is not luminous, a 

 section of the flame being a luminous ring surrounding an ob- 

 scure disc *.'" Hence, it would appear, that, within the present 

 year, it has only been considered as probable, that the flame of 

 a candle is a cone of gas or vapour in a state of combustion at 

 its surface ; and a determination of this point may well be con- 

 sidered the very first step in a scientific investigation of the sub- 

 ject. Though some may be of opinion that this point does not 

 require determination, I shall describe a very simple method, 

 with which I have long been familiar. For this purpose a blow- 

 pipe is all that is necessary ; and one made of glass, having a 

 hollow bulb near its distant extremity, is the most suitable. 

 When the point of the instrument is introduced into the centre 

 of a spirit flame, and the operation of suction is performed, the 

 luminous cone is observed to diminish, or contract in proportion 

 to the degree of suction that is applied ; and by thus extracting 

 the vapour from the interior of the flame, the latter may readily 

 be extinguished. In performing this suction, even with a short 

 tube, the operator is exposed to no risk, farther than that of in- 

 haling a quantity of alcohol in the state of vapour ; and, unless 

 the operation be unnecessarily prolonged or repeated, this is not 

 apt to be followed by any sensible effects. When, after suction 



• Journal of Science for 1826. 



