9 :< 
Mr. Morgan’s Qbjh vaiions and Experiments on 
The molt lingular phenomenon attending a burning body 
is, perhaps, the red appearance it affumes in its laft ftage o £ 
eombuftion. The preceding fadts and obfervations may., 1 
think, help us to explain it. 
1. After a body has continued to burn for forae time, its. 
external lurface is to be regarded as having loft a great portion 
if not the whole of thole rays which the fir ft application o£ 
heat w T as able to feparate. But thefe rays were the indigo, the 
violet, the blue, and perhaps the green. Nothing, therefore, wihr 
remain to be feparated-, but the yellow, the orange, and: the red, 
Confequently, the eombuftion of the body 9 ,in its laft ftateof der 
compofition,_can afl'ume no other than a reddifh appearance. But 
2. Let us confider the external furface of the combuftible 
as. annexed to an inner furface, which may be partly, but not fo 
perfectly decompofed as itfelf : for the violence of the heat will 
be found to leflen in its effects the nearer it approaches to the 
center of the fubftance which is expofed to it. Hence we are 
to conlider the parts which are juft covered by the external fur- 
face as having loft lefs of their component light than the exter- 
nal furface itfelf. Or the former may retain the green rays 
when the latter has loft both indigo, violet, blue, and green., 
3- Thofe parts which are nearer the center of the body 
than either of the preceding rnuft, as they are further from 
the greateft violence of the heat, have loft proportionably 
fewer of their rays. Or w T hile the more external, parts may 
have loft all hut the red, thefe may have loft only the indigo 
and: violet. 
4. The moft central parts may be unaftecled by the heat ; 
and whenever the fire does reach thefe parts, they will immer 
diafely difcharge their indigo, rays, and be decompofed, in the 
gradual 
