ie 4 
Chemistry and Physics. 269 
the shining shell, resting upon the dark combustible matter, the atmos- 
pheric air can hardly penetrate, or rather its oxygen is exhausted and 
consumed. Between the exterior and interior surface, the burning is 
going on with an activity constantly declining, because the interpenetra- 
tion or supply of oxygen is gradually less and | 
But besides this collection of colored shell : may be 
t to to 
ity. 
A flame thus far may be considered as offering three regions :—Ist, a 
central nucleus, which is not luminous, and consists of combustible vapor; 
2dly, an intermediate portion, the true flame, arising from the reaction of 
the air and the combustible vapor, and being composed of a succession of 
‘SUperposed shells, the interior being red, the exterior violet, and the inter- 
Yening ones colored in the proper order of refrangibility ; the cause of this 
difference of color being the declining activity with which the combustion 
Ss on deeper and deeper in the flame. to temperature, the inner’ 
red shell cannot be less than 977° F., and the exterior violet one probably 
More than 2500° F. 3dly, an envelop consisting of the products of com- 
on, exterior to the true flame, shining simply as an incandescent 
te , and its light for the most part overpowered by the brighter portion 
i 
n 
: & . ¥e . i 
Ydize wi i hosphorescent light, quite perceptible 
| elt uateage* here the light is violet, for the supply of 
1 that of the air abundant. The oxydation 
reason, sulphur, as we 
burns blue; but if a piece of it is thrown tr 
potash ignited in a crucible, the light yielded is of intolerable brillian 
ee XXVI, No. 77.—SEPT., 1858. 
