Mr Blackadder on the Constitution of Flame, SS7 



abstract it from the interior of a flame by suction with the 

 mouth. It has, besides, a very offensive odour. 



It has already been stated, that, when the vapour issues in 

 a full stream, it burns with a white flame similar to that of a 

 candle. When the flow of vapour is gradually increased from 

 the smallest quantity that will maintain combustion to the com- 

 plete evolution of the flame, the appearances that are successive- 

 ly exhibited are not unworthy of attention. 



At first the flame is but shghtly convex, and, as viewed 

 from above, there is an exterior ring of a misty blue colour, 

 then a very narrow ring of purple, within that a broad ring of a 

 bright blue colour, and in its centre a circular spot of a sea- 

 green colour, at times very distinct. The green tinge is evi- 

 dently produced by the commencing extrication of yellow light, 

 which, when first perceived, is faint, and has the appearance of 

 a yellow fluid, in a state of slow ebullition. As the flow of va- 

 pour increases, the boihng motion becomes more apparent, then 

 ceases, and as the yellow light rises in a small cone in the cen- 

 tre, the green either disappears, or, for a short time, forms a 

 circle around it. If at this stage of the flame, it be viewed 

 transversely, there is observed a narrow line extending over the 

 yellow cone, which has a very bright purple colour, and which 

 seems to correspond to the broad, dark-blue arch that is ob- 

 served in the flame of alcohol. By directing a momentary 

 puff* of air against the flame of the circular wick, the flame 

 of the vapour is in the course of a few seconds considerably 

 modified. A number of bright yellow lines are seen projecting 

 from the flame, and which proceed from particles of charcoal, 

 that have been formed in the circular flame^ being mixed with 

 the descending vapour, and becoming ignited in passing through 

 the flame at the lower orifice of the glass-tube. As these par- 

 ticles pass through the bright purple line above described, they 

 exhibit a beautiful crimson colour. Does the bright purple light 

 derive its origin from the formation and combustion of cyano- 

 gen, or is it derived from the carbon, as is observed during the 

 combustion of diamond in oxygen gas ? As the flow of vapour 

 increases, the flame expands, but it is still of a yello^^' colour, nor 

 is the white light extricated, until an interior cone is formed^ 

 whose base is above the blue portion of the flame. 



