336 



Mr. J. N. Lockyer. 



[Apr. 29, 



"Mr. Lockyer ('Proc. Roy. Soc.,' vol. 27, p. 308) lias recently* 

 obtained a photograph of the arc in chlorine, which shows the series of 

 fluted bands in the ultra-violet, on the strength of which he throws 

 over the conclusion of Angstrom and Thalen, and draws inferences as 

 to the existence of carbon vapour above the chromosphere in the 

 coronal atmosphere of the sun, which, if true, would be contrary to all 

 we know of the properties of carbon. We cannot help thinking that 

 these hands were due to the presence of a small quantity of nitrogen." f 



It will be seen that on January 8 Mr. Dewar alone attributed the 

 ffutings to hydrocarbon, while on February 2 Mr. Dewar, associated 

 with Mr. Liyeing, attributed them to a nitrocarbon. 



In the latter paper Messrs. Liveing and Dewar published some expe- 

 riments on the spectra of various carbon compounds, and from their 

 observations they have drawn the conclusion that the set of flutings 

 which I have shown to be reversed in the solar spectrum is really due 

 to cyanogen, and that certain other sets of flutings shown by Attfield 

 and Watts to be due to carbon are really due to hydrocarbon. 



As Messrs. Liveing and Dewar do not controvert the very definite 

 conclusions arrived at by Attfield, Morren, Watts, and others, I can 

 only presume that they have taken for granted that the experimental 

 work performed by these men was tainted by the presence of impuri- 

 ties, and that it was impossible to avoid them. I have therefore 

 thought it desirable to go over the ground again, modifying' the expe- 

 rimental method so as to demonstrate the absence of impurities. 

 Indeed, I have started upon a somewhat lengthy research, and have 

 taken a large number of photographs under various conditions, so that 

 to reduce them all will be a work of time. I beg permission, there- 

 fore, in the meantime, to snbmit to the notice of the Society an experi- 

 ment with, a tube containing CC1 4 , which, I think, establishes the 

 conclusions arrived at by prior investigators. And I may add that it 

 is the more important to settle the cjuestion, as Messrs. Liveing and 

 Dewar have already based upon their conclusions theoretical views of 

 a kind w T hich appear to me calculated to mislead, and which I consider 

 to have long been shown to be erroneous. 



As my results, to which I now draw attention, simply endorse former 

 work, it is important to state that former work somewhat at length 

 and in the words of the authors. 



The prior work of Attfield (in 1862) will be gathered from the 

 following extract from his paper (" Phil. Trans.," vol. 152, p. 221 

 et seq.) : — 



" On recently reading Swan's paper by the light that Professors 

 Bunsen and Kirchhoff: have thrown on the subject, I came to the con- 

 clusion that these bands must be due to incandescent carbon vapour ; 



* That is, in 1878- — J. N. L. 



f The italics are mine. — J. N. L. 



