SCIENCE. 



to; 



latter augments and the line disappears, the ultra-violet 

 flutings gradually die out altogether. 



It is philosophical to infer from these observations that 

 not only are the line and flutings in question produced by 

 carbon, but that the blue line (4266), since it is visible at 

 the highest temperature, corresponds to the most simple 

 molecular groupings we have reached in the experiments, 

 and the flutings to others more complex. 



The result to which attention is most to be directed in 

 this place is that touching the two sets of flutings, and 

 should future research justify the double conclusion (1) 

 that these flutings are truly due to carbon, a result I ac- 

 cept, though it is denied by Angstrom and Thalen ; and (2) 

 that the different flutings really represent the vibrations of 

 different molecular groupings ; a great step, and one in the 

 direction of simplification, will have been gained. 



Indeed it is much to be hoped that this ground will be at 

 once worked over again by men of science who are both 

 honest and competent : that the truth is sure to gain by 

 such work is a truism. 



I have so often taken occasion to refer with admiration 

 to the work of Angstrom and Thalen that I shall not be 

 misunderstood when I say that their conclusions, to which 

 such prominence is given, and on which such great stress 

 is laid by Messrs. Liveing and Devvar, rest more upon the- 

 ory and analogy than upon experiment. 



Their work, undertaken at a time when the existence of 

 so-called " double spectra " was not established upon the 

 firm basis that it has now, and when there was no idea that 

 the spectrum recorded for us the results of successive dis- 

 sociations, gave, as I have previously taken occasion to 

 state, the benefit of the doubt in favor of flutings being due 

 to compounds, and it was thought less improbable that 

 cyanogen or acetylene should have two spectra than that 

 carbon or hydrogen should possess them. 



Indeed, later researches have thrown doubt upon the 

 view that the fluted spectra of aluminium and magnesium 

 are entirely due to the oxides of those metals instead of to 

 the metals themselves — and this is the very basis of the 

 analogy which Angstrom and Thalen employed. 



The importance of the observations to which I have re- 

 ferred is all the greater because of the general conclusions 

 touching other spectra which may be drawn from them. 

 Thus from what I have shown it will be clear that if my 

 view is correct, the conclusions drawn 1 by Messrs. Liveing 

 and Dewar from the assumed hydrogen-carbon bands 

 touching both the spectrum of magnesium and the spectra 

 of comets, are entirely invalid. These conclusions are best 

 given in their own words : — 



"The similarity in the character of the magnesium-hy- 

 drogen spectrum, which we have described, to the green 

 bands of the hydrocarbons is very striking. We have sim- 

 ilar bright maxima of light, succeeded by long drawn-out 

 series of fine lines, decreasing in intensity towards the more 

 refrangible side. This peculiarity, common to both, im- 

 pels the belief that it is a consequence of a similarity of 

 constitution in the two cases, and that magnesium forms 

 with hydrogen a compound analogous to acetylene. In this 

 connection the very simple relation (2 : 1) between the 

 atomic weights of magnesium and carbon is worthy of note, 

 as well as the power which magnesium has, in common 

 with carbon as it now appears, of combining directly with 

 nitrogen. We may with some reason expect to find a mag- 

 nesium-nitrogen spectrum. . . . 



" The interest attaching to the question of the constitu- 

 tion of comets, especially since the discovery by Huggins 

 that the spectra of various comets are all identical with the 

 hydrocarbon spectrum, naturally leads to some speculation 

 in connection with conclusions to which our experiments 

 point. Provided we admit that materials of the comet con- 

 tain ready-formed hydrocarbons, and that oxidation may 

 take place, then the acetylene spectrum might be produced 

 at comparatively low temperatures without any trace of the 

 cyanogen spectrum or of metallic lines. If, on the other 

 hand, we assume only the presence of uncombined carbon 

 and hydrogen, we know that the acetylene spectrum can 

 only be produced at a very high temperature, and if nitro- 

 gen were also present that we should have the cyanogen 

 spectrum as well. Either, then, the first supposition is the 



1 Paper read February 12, 1880. 



true one, not disproving the presence of nitrogen, or else 

 the atmosphere which the comet meets is hydrogen only, 

 and contains no nitrogen." 



The importance of the question here treated of comes out 

 very well from these two extracts. We find the same spec- 

 tral phenomenon at once called into court, and very prop- 

 erly called in, both to suggest the existence of chemical 

 substances of which the chemist has never dreamt, and to 

 explain the chemical nature of a large group of celestial 

 bodies. 1 



There is little doubt that when a complete consensus of 

 opinion is arrived at among the workers, other suggestions 

 more far reaching still will be derived from the prosecution 

 of these inquiries. For the present, however, the chief 

 point to bear in point is that both in line-spectra and in 

 fluted spectra we have indications which I think favor the 

 view that in each case the origin is compound rather than 

 simple. — Nature. J. Norman Lockyer. 



Oban, July 20. 



PHYSICAL NOTES. 



From the above article we see that as far back 

 as 1878, Mr. Lockyer communicated to the Royal 

 Society a paper in which the conclusion was drawn 

 that vapor of carbon was present in the solar at- 

 mosphere. This inference was founded upon experi- 

 ments similar to those of Attfield and Watts, who 

 showed that flutings are always present in different 

 compounds of carbon exposed to the action of heat and 

 electricity. This observation of Lockyer has been called 

 in question by Liveling and Devvar, as they have found 

 it an almost impossible problem to eliminate hydrogen 

 from masses of carbon. This latter view has been long 

 held by Edison, who, in a great number of experiments, 

 some of which were participated in by Prof. Young, has 

 found at the enormous heat developed by igniting a fine 

 carbon thread voVu of an inch diameter, of high resist- 

 ance, in air vacuum, until a light of 80 candles is reached, 

 that only a carbon spectrum is given, until just a few 

 seconds before the rupture of the loop, when a sharply 

 defined hydrogen spectrum is observed. On the other 

 hand, in an observation of the purified spectrum of car- 

 bon tetrachloride, Mr. Lockyer {Nature, August 5th) 

 found only carbon appeared at high temperatures. It is 

 an excellent index ol the spirit of unbiased investigation 

 in the author of {Nature, December, 1878) The Hypo- 

 thesis that the so-called Elements are Compound Bodies, 

 and still later, of the Universal Hydrogen Hypothesis, to 

 learn from Mr. Lock>er that, both in line and fluted 

 spectra, he thinks we have indications which lavor the 

 view that in each case the origin' is compound rather 

 than simple. 



In a communication from William Huggins, F.R.S., re- 

 ceived June 16th, r88o, and published in the American 

 Journal of Science for August, are embodied some observa- 

 tions on the nature of the spectrum of water, which may 

 give rise to a question of priority. It appears that Dr. 

 Huggins made a photograph of the flame of hydrogen burn- 

 ing in air, December 27, 1879, but did not publish the fact. 



On June last, Messrs. Liveing and Dewar state, in a 

 paper read before the Royal Society, that they have ob- 

 tained a photograph of the ultra violet part of the spectrum 

 of coal gas burning in oxygen, and in a note dated June 

 8th, they add that they have reason to believe that this re- 

 markable spectrum is not due to any carbon compound, 

 but to water. Professor Stokes (whose well-known mono- 

 graph in Phil. Trans., 1852, has furnished so much sugges- 

 tive material for others to work upon in this very line), 

 authorizes the statement that Dr. Huggins, in a let- 



1 With special reference to this last question, that of cometary spectra, 

 one of acknowledged difficulty, I may perhaps be permitted to add here 

 by way of note that the view I put forward some years ago touching the 

 relation to this spectrum to that of the nebulae has been lately strength- 

 ened by the observation that at a low temperature one of the brightest 

 lines in the spectrum of iron is that coincident with the chief line in the 

 nebula-spectrum. 



