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



from the corresponding parts of my own reasonings, in the same 

 sense as two separate links of a chain are different from the same 

 links when held together by a third, connecting link. Prof. 

 Tyndall states that the platinum is rendered "white" by oscil- 

 lations which are invisible; and he hence concludes at once 

 that there is a " breaking up of long periods into short ones." 

 This, however, is simply a non-sequitur. I founded my own 

 conclusions concerning the origin of lime-light, &c, upon the 

 evident deficiency of the oxyhydrogen-flame in Newtonic or 

 luminous rays, and upon its probable poverty in Ritteric or so- 

 called chemical rays, as compared with lime-light. And what I 

 had thus at first but conjectured, regarding the Ritteric rays, was 

 soon after corroborated by Prof. W. A. Miller's experiments on 

 the comparative photographic effects of the oxyhydrogen-flame 

 in its pure state, and of lime-light produced by the oxyhy- 

 drogen jet*. 



2. Before adverting to the second, principal part of Professor 

 Tyndall' s argument, a word or two may be apposite regarding 

 his intermediate statements. The change of refrangibility which 

 takes place in the oxyhydrogen-flame by the introduction of 

 lime, or in the simple hydrogen-flame by the introduction of 

 platinum, according to Prof. Tyndall, differs from that taking 

 place in fluorescence "in its being in the opposite direction." This, 

 as shown, Prof. TyndalFs reasoning does not prove. He states 

 also that the platinum is " heated by the collision of the molecules 

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

 form." I expressed the same idea by saying that the act of 

 transmutation, in the case of lime-light, took place "in statu 

 nascenti, as it were," of the raysf. 



3. The concluding part of Prof. TyndalPs induction affirms 

 that " 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 aether oscillating 

 at the same rate." In our present ignorance concerning the 

 mode in which material particles act upon each other, or of the 

 real constitution of aether, an assertion like the above will scarcely 

 be considered as contributing to render "a chain of reasoning" 

 "rigid." In my own case, I reasoned concerning this matter 

 as follows J : — " Every kind of radiation possesses, with respect to 

 any given substance, a certain heating power, which depends 

 (1) on the amplitudeof the given ray; (2) on the absorptive 

 power of the given substance for the given ray ; and (3) in some 

 unknown manner on the length of undulation of the given radia- 

 tion. Any kind of radiation may, hence, be competent to raise 



* Report of the British Association, 1863, p. 95. f Ibid. p. 101. 



% See 'Reader/ September 26, 1863, p. 349. col. 2. 



