Mr Blackadder on the Constittition of' Flame. 



The flame of a candle differs but little from that of the va- 

 pour, or that of oil burned without a wick. For, after the wick 

 is carbonized, as long as it is completely enveloped by the flame, 

 and is not in contact with it, it undergoes no particular change. 

 The charcoal becomes more consolidated, but none of it seems 

 to escape, or to be carried off by the vapour ; and hence, on the 

 present occasion, the wick may be viewed simply as a porous 

 solid, projecting into the centre of the flame. In such a flame 

 as that of a candle, the following parts may be distinguished : 



1^^, A blue portion, which extends from the base to about 

 the middle of the flame. Its extent may, in most cases, be 

 traced by the eye, but its height may always be determined by 

 means of a blowpipe. This may be termed the essential part 

 of the flame, which may exist without the white light, but with- 

 out which the latter cannot be produced. It is at least princi- 

 pally at this part of the flame that water is formed by the 

 union, of hydrogen, with the oxygen of the atmosphere. 



9,dly^ An attenuated opaline brush over the whole exterior 

 surface of the blue part of the flame. This brush can readily 

 be distinguished as high as the middle of the flame, where the 

 blue portion terminates ; and perhaps, strictly speaking, it does 

 not extend higher. But, from its apparent termination to the 

 apex of the flame, there is a somewhat similar, but extremely 

 attenuated brush, which has a dusky yellow colour, readily dis- 

 tinguished in small flames, but seldom to be observed in large 

 flames, without the aid of opaque skreens. How this opaline 

 brush is produced, or in what it differs from the other parts of 

 the flame, remains perhaps to be determined. From the blue 

 part of the flame, water is very copiously discharged in the form 

 of steam. When a polished piece of metal is approached to it, 

 even at its base, there is a copious and instantaneous deposition 

 of moisture on its surface. It is not improbable, therefore, that 

 the brush is produced mechanically by the steam as it issues 

 from the flame ; and this would enable us to account for its be- 

 coming nearly invisible above the blue portion of the flame of a 

 Candle, and for its presence over the whole surface of a blue 

 flame, such as that of alcohol. 



Sdly, A cone of yellowish white light, commencing on the 

 inner surface, and at a short distance from the base of the blue 

 portion. On the inner surface of the blue portion, this cone is 



