30 Mr. P. Smyth on Carbon and Hydrocarbon 



Chemical Parentage of the Spectrum under discussion. 



That spectrum is, says Br. Watts, the spectrum of carbon, 

 and not of a hydrocarbon or any other compound of carbon. 



This is so far very plain and distinct as an assertion, and indi- 

 cates that the learned world of London, as represented by the 

 Philosophical Magazine, is not yet advanced beyond the position 

 it was in when I sent my first paper to the Royal Astronomical 

 Society in May 1871, and gave then such extracts from the 

 authorities on either side as showed, I verily thought, that the 

 spectroscopists declaring for pure carbon, in opposition to those 

 pronouncing for carbohydrogen, were blundering little less than 

 the perpetual-motion men of last century. 



For why ? Carbon is a simple element in chemistry ; and to 

 give its spectrum at all as a luminous and discontinuous one, it 

 must be driven off in vapour, glowing and incandescent. 



This is the condition for any and every chemical element to give 

 forth its spectrum under the prism ; and some elements will send 

 out their vapour easily enough at very moderate temperatures in 

 any common candle-name, while others require much more in- 

 tense heat ; for even in a powerful blowpipe-flame they only 

 become hot and luminous as solid bodies, without rendering out 

 any vapour, until the aid of oxygen or the electric spark is 

 brought in. But carbon ! why, that has never been volatilized 

 yet by any contrivance or accumulation of contrivances by mo- 

 dern men; so that M. Lielegg in Austria, and Mr. Crookes in 

 the ' Chemical Journal ' in England, pronounced years ago that 

 thejnerely talked-about vapour of carbon was only an hypothesis, 

 a delusion. I have, too, myself seen the full power of a 12-horse 

 steam-engine converted by Mr. Wylde of Manchester into elec- 

 tric currents, and the whole directed for several minutes through 

 a little thin pencil of carbon in a manner that would have 

 melted and dissipated the same bulk of platinum over and over 

 again, but with no other effect than merely to make the carbon, 

 as a solid, white-hot, or just as I have found chloride of magne- 

 sium to go on glowing as a hot solid but nothing more (unless 

 to show faintly the lines of calcium and sodium impurities) in 

 an ordinary blowpipe-flame. 



Hence, then, if man has never volatilized carbon, human eye 

 has never yet knowingly seen its spectrum, and can form no 

 idea from theory of what it will be like, except that it will be 

 totally different in kind and species from the many-banded 

 spectrum of ranks of closely arranged perspectives of lines which 

 has been so positively mistaken for it by certain parties. For 

 as Mr. Norman Lockyer has recently shown, that kind of spec- 

 trum indicates at once a chemical compound of two or more 



