338 Observations on the Flame of a Candle. [May, 
surface; and he has asserted that, were the flame solid, the wick 
could not be seen through it; for flame, he adds, “ is an opake 
substance, as any one may satisfy himself by trying to read a book 
through the upper part of the flame of a candle.” 
Having paid some attention to the appearance of the flame of a 
candle, with the advantage of a previous perusal of the papers just 
mentioned, it appears to me that my observations are more precise 
than those already made, on one or two points, and impart some 
little additional information. I consider it, therefore, right to make 
them public, because every improvement, however slight, in our 
knowledge of this subject, derives some importance from the con- 
nexion which necessarily exists between such knowledge and the 
means resorted to for increasing the beneficial effects of flame, or 
for preventing its destructive agency. 
The first observation which I made on looking at the flame of a 
candle was, that the luminous portion of it is surrounded on all 
sides by a flame nearly invisible. The reason why it is not easily 
seen is, that the eye is not in a condition to observe the feeble light 
emitted by this exterior flame while it is under the influence of the 
brilliant light emitted from the surface of the interior flame; but if 
this last-mentioned light is diminished by any means, then the ex- 
terior flame becomes more apparent. Thus it is better seen when 
a candle burns with a dim light for want of snuffing ; still better 
when the flame of a candle is in extensive contact with a metallic 
surface, by which its light is materially diminished; and best of all 
in those flames which give very little light, as in that of spirits of 
wine. The weakly luminous exterior flame is the part really under- 
going the process of combustion and producing heat; and there 
seems reasons for believing that no part of the atmospheric oxygen 
penetrates beyond it, and that the heat of other parts is merely ac- 
uired by contact with it. 
I find that, when a piece of wire-gauze of about 900 meshes to 
the square inch is cut as nearly as possible into the size and shape of 
the flame of a candle, or rather of that part of it which rises above 
a short wick, and the central wire is left to descend about three- 
fourths of an inch below the rest, to represent a wick, so that this 
wire may be thrust down the middle of the true wick of a candle to 
support the gauze in a perpendicular position, it makes, when the 
candle is lighted, a vertical section of the flame; and if the flame 
thus bisected is screened from currents of air, it traces upon the 
wire-gauze marks of the different actions of its several parts; the 
edge of the wire-gauze in the weakly luminous exterior flame be- 
comes red-hot and peroxidized; the part next to this, which cuts 
through the strongly luminous surface, becomes thickly coated with 
charcoal, which forms a black line within the red one, and corres- 
ponds with it in form, which is that of a sugarloaf; within this line 
the wires are but slightly blackened, and thus mark the space occu- 
pied within the flame by the gases and inflammable vapour issuing 
from the wick. 
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