the Light of Bodies in a State of Comb u ft ion . rp.^ 
■'Jt. The blue colour of a fulphurcous flame iu pure air is 
changed into a dazzling white. 
3. The flame of inflammable air, when mixed with ni- 
trous air, is green. It is white {Iron gly tinged with the indigo 
and violet when mixed with common air; but when mixed 
with dephlogifticated air, or furrounded by it, the brilliancy 
of its flame is moll: Angularly beautiful. 
If the preceding faCts prove that light, us an heterogeneous 
body, is gradually decompofed during com bullion ; if they 
prove, iikewife, that the indigo rays efcape with the leaf! heat, 
and the red with the greateff ; I think we may rationally ac- 
count for feveral Angularities in the colours of different flames. 
If a piece of paper, impregnated with a folution of copper in 
the nitrous acid, be fet on Are, the bottom and Ades of the 
flame are always tinged with green. Now this flame is evi- 
dently in that weak ffate of decompoAtion, in which the mo ft 
refrangible rays efcape in the greateft abundance ; but of thefe 
mfs the green efcape moft plentifully through the unignited 
vapour and that portion of the atmofphere which feparates the 
eye from the flame. The peculiarity which I have now endea- 
voured £0 account for may be obferved in the greatefl: perfection 
In brafs ffounderies. The heat in this inftance, though -very 
ftrong, is fcarcely adequate to the decompoAtion or the metallic 
vapour which efcapes from the melted brafs. A very Angular 
flame therefore appears to the eye ; for while its edges are green 5, 
its body is fuck as to give the objeCls around a very pallid or 
ghaftly appearance, which is the confequence of its wanting 
that portion of red rays which isyiecefiary to make a perfeCt 
white. 
C c % 
The 
