ON THE TRANSMUTATION OF SPECTRAL RAYS. 95 
tually effected belong to the first series only, extending from (1) to (6), any 
one of the transmutations from (7) to (12), which, instead of as the former a 
diminution, imply an increase of refrangibility in the transmuted beam, would. 
possess an interest of its own if accomplished, More particularly would this 
be so in the case of the transmutation (10), which is the counterpart or con- 
verse of the transmutation (4) occurring in fluorescence, and which, from its 
concerning exclusively visible rays, would be, at once, easiest to prove, and, 
next to (8), practically most important. _ 
It is the object of this paper to propose three several experiments, which, 
it is supposed, would be found capable of realizing the two transmutations (8) 
and (10) spoken of above. The mode of conducting each of them, as applica- 
ble to the transmutation (8), is described in what follows. 
Experiment I, 
4, The oxyhydrogen flame is well known to excite in lime, chalk, and 
other similar substances a most brilliant light, if brought into contact with 
them. The flame by itself, on the contrary, is but sparingly visible, and hence 
deficient in Newtonic rays; whilst, from the experiment mentioned below*, it 
appears similarly poor in Ritteric rays. Considering these circumstances, 
and the high ecalefactory power of the oxyhydrogen flame, it seems fair to 
conclude that the rays principally emitted by it are of the Herschellic species, 
Now the Newtonie rays emanating from the flame upon the introduction of 
lime, &c.,—which, there is reason to believe, are accompanied also by a strong 
beam of Ritteric rays,—cannot but be owing to a transmutation, in statu 
nascenti so to speak, of the rays originally emitted 7 the flame when free | 
from foreign matter, and therefore most probably evidence a phenomenon of 
the kind which it is intended to produce. But, to render the experiment com- 
pletely similar to those of fluorescence, the following arrangement would have 
to be adopted. , 
Let two conjugate mirrors of large size be placed opposite to each other, one 
containing in its focus the oxyhydrogen flame, the other a piece of chalk or 
lime. Let, further, absorbents be employed to cut off as many of the Newtonic 
and Ritteric rays as the flame may be found to emit, from access to the focus 
wherein the lime is placed. If the mirrors are of sufficient size to render the 
temperature at the distant focus approximately equal to that of the flame 
itself, there is eyery reason to believe that the lime therein contained will 
begin to shine out, or, in other words, will emit Newtonic rays consequent 
upon the incidence of Herschellic rays, in the same way as a fluorescent sub- 
stance emits Newtonic rays consequent upon the incidence of Ritteric rays, 
The possible duration of the luminosity thus produced beyond the time of 
* Prof. W. A. Miller has observed (see Chem. News, March 21, 1863) that the photo- 
graphic impression produced by an oxyhydrogen flame, after twenty seconds’ exposure of 
the sensitive paper, was very faint; the impression produced by lime-light, after the same 
time, being, on the contrary, yery strong. Seeing that the chemical action of Newtonic rays 
is generally less than that of Ritteric rays, this observation tends to demonstrate the defi- 
ciency of the oxyhydrogen flame in Ritteric rays when in its natural state, and at the same 
time to indicate that the transmutations taking place in the flame upon the introduction of 
lime are of the nature supposed in the text. 
[On the reading of the present Paper at Newcastle, Prof. Miller, being present, mentioned 
the following further fact, of similar tendency :—The rays of the oxyhydrogen flame, if con- 
centrated by a glass lens upon an ordinary thermoscope, produce little or no effect before 
the introduction of lime, but a considerable effect after its introduction. This seems to be 
owing to the diminished absorption which glass exercises upon the more refrangible rays 
as compared with the less refrangible.] ; 2 
