312 



NATURE 



[^Augusi 5, 1880 



It is philosophical to infer from these observations tliat 

 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, coiresponds to the most simple 

 molecular grouping 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 (i) 

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

 accept, 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 Dewar, rest more 

 upon theory and analogy than upon experiment. 



Their work, undertaken at a time when the exibtence 

 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 suc- 

 cessive dissociations, gave, as I have previously taken 

 occasion to state, the benefit of the doubt in favour of 

 flutings being due to compounds, and it was thought less 

 improbable that cyanogen or acetylene should ha\'e 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 Thalfen employed. 



The importance of the observations to which I have 

 referred is all the greater because of the general con- 

 clusions 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 ' 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- 

 hydrogen spectrum, which we have described, to the 

 green banJs of the hydrocarbons is very striking. We 

 have similar bright maxima of light, succeeded by long 

 drawn-out series of fine Unes, decreasing in intensity 

 towards the more refrangible side. This peculiarity, 

 common to both, impels 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. Wc may 



* P.il cr read Februarj* ii, i3So. 



with some reason expect to find a magnesium-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 contain ready-formed hydrocarbons, and that 

 oxidation may take place, then the acetj'lene 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 nitrogen were also present that we 

 should have the cyanogen spectrum as well. Either, then, 

 the first supposition is the 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 spectral phenomenon at once called into court, and 

 very properly 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.^ 



There is little doubt that when a complete consensus 

 of opinion is arrived at among the workers, other sugges- 

 tions more far reaching still will be derived from the 

 prosecution of these inquiries. For the present, however, 

 the chief point to bear in mind is that both in line-spectra 

 and in fluted spectra we have indications which I think 

 favour the view that in each case the origin is compound 

 rather than simple. J. Norman Lockyer 



Oban, July 20 



THE EDUCATION DEBATE 



THE chorus of approval with which Mr. Mundella's 

 report on the progress of elementary education was 

 received on Monday cannot but be gratifying to all who 

 have at heart the highest welfare of the country. With 

 one or two unimportant exceptions— members whose vision 

 is so bizarre as to discern communism in the education of 

 the children of the working classes, and who connect the 

 increase of weeds with the spread of education— what 

 criticism there was referred to details of method. All the 

 members whose opinions are of any weight agreed that vast 

 good had resulted to the country by the working of the 

 Code. As to the special subjects, among which science 

 is included, the weight of opinion was decidedly in favour 

 of their retention. The greatest friends of the Fourth 

 Schedule will admit that there is still much room for im- 

 provement in the teaching of these subjects ; it cannot be 

 expected that so great a novelty in the system of ele- 

 mentary education in the country can all at once be 

 taught to perfection. About the success of the compulsory 

 system of education it may be said that the House was all ■ 

 but unanimous. The analogy between the treatment of 



. With speci.->l reference to this last question, that of cometary spectra 

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

 hv wiv of note thtt the view I put forward some years .->go touchmg the 

 re'^alSJof this spectrum tl that oFthe nebute has bee" la^'V "-"S/^™^ 

 bv the observation that at a bw temperature one of the brightest hues in the 

 spectrum 7iron is that, coincident with the^chief Jme m._the_ nebula- 

 pecirum. 



