156 Intelligence and Miscellaneous Articles. 



In their paper " On the Spectra of the Compounds of Carbon " 

 (Proe. R»oy. Soc. vol. xxx. p. 494), Professors Liveing and Dewar 

 show that these two groups indicate the presence of cyanogen, and 

 are not to be seen in the absence of nitrogen. If this be the case, 

 the photograph gives undoubted evidence of the presence of nitrogen 

 in the comet, in addition to the carbon and hydrogen shown to be 

 there by the bright groups in the visible part of the spectrum. On 

 this hypothesis we must further suppose a high temperature in the 

 comet, unless the cyanogen is present ready formed. 



I should state that Mr. Lockyer regards the two groups in the 

 photograph, and the groups in the visible spectrum, as due to 

 the vapour of carbon at different heat-levels (Proc. Roy. Soc. 

 vol. xxx. p. 461). 



It is of importance to mention the strong intensity in the photo- 

 graph of the lines 3883 and 3870, as compared with the continuous 

 spectrum and the faint bright group beginning at 4230. At this 

 part of the spectrum, therefore, the light emitted by the cometary 

 matter exceeded by many times the reflected solar light. I reserve 

 for the present the theoretical suggestions which arise from the new 

 information which the photographs have given us. — Proceedings of 

 the Royal Society, No. 213, 1881. Communicated by the Author. 



THE EXISTENCE OF THE LUMINIFEROUS .ETHER. 

 To the Editors of the Philosophical Magazine and Journal. 



Gentlemen, 

 In the papers which I have communicated to your Journal on 

 the above subject, 1 have endeavoured to show that the phenomena 

 of Optics can be explained without calling in the aid of any sub- 

 stance of the nature of the aether, and also that what may be termed 

 ordinary matter possesses the requisite properties to enable it to 

 act as the medium which serves for the transmission of the undu- 

 latory movement. Although I have not anywhere in these papers 

 laid claim to originality, yet I was quite unaware at the time of 

 writing that the same ideas had been previously propounded. Until 

 after the publication of the second of these papers, I regret to say 

 that I had not read ' The Correlation of Physical Forces.' I find 

 that so far back as 1842 the distinguished author of this work had 

 published his views on the subject, which in almost every particular 

 are the same as those held by myself. All credit for originality is 

 therefore due to Sir W. E. Grove ; and it is probable that, if I had 

 known how completely he had anticipated the conclusions to which 

 I have arrived, my papers would never have been written. As it 

 is, however, it is due to Lord Justice Grove to make this statement ; 

 and in doing so I take the opportunity of expressing the pleasure 

 one feels at finding his views shared by so eminent an authority. 

 I have the honour to be, Gentlemen, 



Your obedient Servant, 



Ek:nt;st H. Cook. 



