On the Production of Light by Chemical Action. 167 
was actually the fact. There was a spectrum so beautiful that it 
is impossible to describe it by words or depict it in colors. It w 
crossed throughout its extent by black lines, separating it into well 
marked divisions. I could plainly count four great red rays of 
definite refrangibility, followed by one orange, one yellow, and 
seven green; whilst in the more refrangible spaces, were two ex- 
tensive groups of black lines, recalling somewhat from their posi- 
tion, but greatly exceeding in extent, Fraunhofer’s lines marked 
and H in the sun’s rays. I shall return to the consideration of 
this spectrum and to the nature of fixed lines presently, here only 
making the remark, that the burning of cyanogen, both as respects 
the color of the light, and the occurrence of fixed lines, is a di- 
rect consequence of the principle I am establishing. _ 
The unassisted eye detects two well marked regions in the cy- 
anogen flame ; a greenish gray stratum on the outside, and a lilae 
colored nucleus within. Decomposed by the prism, a horizontal 
element of this flame shews that the exterior shell contains all 
the prismatic colors, except perhaps the yellow ; but the green, 
the blue and the violet greatly predominate. The interior lilac 
flame is the source of the bright spectrum with fixed lines just 
scribed. — 
V. Continuation of the same principle in the case where com- 
bustion is carried on in oxygen gas, instead of atmospheric atr. 
If the principle that high refrangibility is connected with in- 
tense chemical action be true, it must hold good when the nature 
of the atmosphere in which the burning is carried forward is 
changed. If instead of being common air it is oxygen gas, we 
ought to be able to foresee the result. Carbonic oxyd, when 
made to burn in that gas, should not change its tint; because if 
the air can carry on the process to its maximum effect, oxygen 
can do no more. But the result should be just the reverse with 
cyanogen, which, if made to burn in oxygen, should be capable 
of emitting rays of a higher refrangibility. . 
__Foreseeing this, I proceeded to submit the two gases to the test 
of experiment ; and first arranged the carbonic oxyd that its spec- 
tram might be examined in the telescope, as already described. 
Then, causing a clean bell jar full of oxygen to be inverted over 
it, the flame diminished somewhat in size, emitted a slight crack- 
ling sound, but retained its color unchanged. Its emg ap- 
peared precisely the same, both as respects extent, and the a 
bution of color, whether the burning took place in oxygen gas, 
or in atmospheric air. 
If trmnce be made to burn in oxygen, we should expect that 
it would lose to a great extent its characteristic lilac tint, and 
emit a whiter light. It was therefore very interesting to find, 
that the moment the flame was immersed in oxygen, it lost much 
of its pinkish color, and became of a dazzling brilliancy. And 
