Dr. C. K. Akin on Ray-Transmutation. 555 



the oxyhydrogen-flame, was produced by a change in the period 

 of vibration. By a different mode of reasoning T arrived at the 

 same conclusion myself, and published the cod elusion subse- 

 quently." The reference appended to the last sentence is to "Phil. 

 Trans, vol. cliv. p. 327." The following passage is taken from a 

 paper read before the Royal Society by Prof. Tyndall on March 

 17, 1864*, and will be found in the place indicated, at p. 360 : — 



" Professor Stokes has demonstrated that a change of period is 

 possible to those rays which belong to the violet and extra- violet end 

 of the spectrum, the change showing itself by a degradation of the 

 refrangibility. That is to say, vibrations of a rapid period are ab- 

 sorbed, and the absorbing substance has become the source of vibra- 

 tions of a longer period. Efforts, I believe, have been made to 

 obtain an analogous result at the red end of the spectrum, but hitherto 

 without result ; and it has been considered improbable that a change 

 of period can occur which should raise the refrangibility of the light 

 or heat. Such a change, I believe, occurs when we plunge a plati- 

 num wire into a hydrogen-flame. The platinum is rendered white 

 by the collision of molecules whose periods of oscillation are incom- 

 petent to excite vision. There is in this common experiment an 

 actual breaking up of the long periods into short ones — a true ren- 

 dering of un visual periods visual. The change of refrangibility dif- 

 fers from that of Professor Stokes, firstly, in its being in the oppo- 

 site direction — that is, from low to high ; and secondly, in the cir- 

 cumstance that the platinum is heated by the collision of the mole- 

 cules of aqueous vapour, and before their heat has assumed the 

 radiant form. But it cannot be doubted that the same effect would 

 be produced by radiant heat of the same period, provided the motion 

 of the aether could be raised to a sufficient intensity. The effect in 

 principle is the same, whether we consider the platinum wire to be 

 struck by a particle of aqueous vapour oscillating at a certain rate, 

 or by a particle of sether oscillating at the same rate. And thus, I 

 imagine, by a chain of rigid reasoning, we arrive at the conclusion 

 that a degree of incandescence, equal to that of the sun itself, might 

 be produced by the impact of waves, of themselves incompetent to 

 excite vision" *. 



1. The important parts of the above passage are the two couples 

 of sentences, the one beginning with the words " The platinum is 

 rendered white," and concluding with " unvisual periods visual ; " 

 and the other beginning with the words "But it cannot be 

 doubted," and concluding with " at the same rate." The first 

 two sentences in this " chain of reasoning " are (C different " 



* To this passage the following footnote is appended : — " Some time after 

 this was written I learned that Dr. Akin had previously inferred, from the 

 paucity of luminous and extra-violet rays in the hydrogen-flame, that its 

 periods must bs extra-red. And he deduced from this that the heating of 

 a platinum wire in a hydrogen-flame must consist of a change of period. 

 A . . . communication from Dr. Akin on this and kindred subjects will be 

 found in the 'Reader ' for the 26th of September, 1863.— April 5, 1864. 



202 



