July 2 2, 1880] 



NATURE 



283 



researches relating to invertebrates, cryptogams, &c., is con- 

 tinued as usual. 



The Rivue des Sciences NattireUes, June 15, contains: M. 

 Hesse, description of two new Crustacea, male and female, of the 

 genus Dinemoura (D. mustehi Ucvis) (Plate I). The figures are 

 coloured from li-zing specimens ; the species lives not in the 

 interior of ti.e shark, but on its skin, and its mode of fixation is 

 minutely described. — M. Duval-Jouve, on the species of Vulpia 

 to be found in France. — D. A. Godron, on the giant maize (Zea 

 caragua). — M. Rietsch, on Bobretzki's studies on the formation 

 of the blastoderm and germinal lamellce in insects. — A. Villot, 

 the synchronism of the marls andclays \vith lignite of Hauterives 

 with the group of St. Aries. — M. S. Jourdain, on a very simple 

 form of the group of worms Prothdminthm hcsd (S. }.)=?/«- 

 ihosia leptolamr, Giard (Plate 2). — Scientific review of recent 

 French WTitings on zoology, botany, and geology. 



SOCIETIES AND ACADEMIES 

 London 



Royal Society, June 17. — " On the Spectrum of the Flame 

 of Hydrogen," by William Huggins, D.C.L., F.R.S. 



Messrs. Liveing and Dewar state, in a paper read before the 

 Royal Society on June 10, that they have obtained a photograph 

 of the ultra-violet pai-t of the spectrum of coal gas burning in 

 oxygen, and in a note dated June 8 they add that they have 

 reason to believe that this remarkable spectrum is not due to any 

 carbon compound but to water. 



Under these circumstances I think that it is desirable that I 

 should give an account of some experiments which I made on this 

 subject some mouths since without wailing until the investigation 

 is more complete. 



On December 27, 1S79, I took a photograph of the flame of 

 hydrogen burning in air. As is well known, the flame of 

 hydrogen possesses but little luminosity, and shows no Hues or 

 bands in the visible part of the spectrum, except that due to 

 sodium as an impurity. 



Prof. Stokes, in his paper •■' On the Change of Refrangibility 

 of Light,"' liad stated that "the flame of liydrogen produces a 

 very strong effect. The invisible rays in which it so much 

 abounds, taken as a whole, appear to be even more refrangible 

 than those which come from the flame of a spirit lamp." I was 

 not, however, prepared for the strong group of lines in the ultra- 

 violet which, after an exposure of one minute and a half, came 

 out upon the plate. 



Two or three weeks later, about the middle of January, iSSo, 

 I shom-ed this spectrum to Prof. Stokes, and we considered it 

 probable that this remarkable group was the spectrum of water. 

 Prof. Stokes permits me to mention that, in a letter addressed to 

 me on January 30, he speaks of "this novel and interesting 

 result," and makes some suggestions as to the disputed question 

 of the carbon spectrum, 



I have since that date taken a large number of photographs of 

 the spectra of different flames, in the hope of being able to 

 present the results to the Royal Society, when the research was 

 more complete. I think now that it is desirable that I should 

 describe the spectrum of the flame of hydrogen, but I shall 

 reserve for the present the experiments which relate to the 

 presence of carbon and its compounds. 



The spectrum of the flame of hydrogen burning in air is 

 represented in the diagram. It consists of a group of lines 

 which terminates at the more refrangible limit in a pair of 

 strong lines, \ 3062 and A 306S. At a short distance in the 

 less refrangible direction, what may perhaps be regarded as 

 the group proper commences with a strong line, A 3090. 

 Between the strong line \ 306S and the line A. 3090 there is a 

 line less bright, A 3080. Less refrangible than the line A 3090 

 are finer hues at about equal distances. The lines are then fine 

 and near each other, and appear to be arranged in very close 

 pairs. There is a pair of fine, but very distinct lines, A 3171 

 and A 3167. In this photograph the group can be traced to 

 about A 3290. This group constitutes tlie whole spectrum, 

 which is due probably to the vapour of water. 



I then introduced oxygen into the flame, leaving a small excess 

 of hydrogen. A spectrum in all respects similar came out upon 

 the plate. I repeated the experiment, taking both spectra on 

 the same plate. Through one-half of the slit the spectrum of 

 the oxyhydrogen flame was taken. This flame was about 7 

 ' Phil. Trans, f 1552, p. 539. 



inches long, and the spectrum taken of a part of the flame 2 

 inches from the jet. The oxygen was then turned off, and the 

 quantity of hydrogen allowed to ^remain unaltered. A second 

 spectrum with an exposure of the same duration was then taken 

 through the second half of the slit. On the plate the two spectra 

 are in every respect similar, and have so exactly the same 

 intensity that they appear as one broad spectrum. 



In all these experiments a platinum jet which had been care- 

 fully cleaned was used. 



In these experiments the two gases met within the blowpipe 

 and issued in a mixed state. 



The jet was removed, and a flame of hydrogen was surrounded 

 with oxygen. This spectrum shows some additional lines. In 

 this ca^e the jet was brass, and in this or some other way 

 impurities may have been introduced ; and I should at present 

 incline to the view that the additional lines about A 3429 and 

 ^ 3473! 3"<i 'lie groups more refrangible than A 3062, do not 

 belong to the water spectrum, but to impurities. 



Coal-gas Mas substituted for hydrogen in the oxyhydrogen 

 blowpipe, and oxygen admitted in as large a proportion as 

 possible. The inner blue flame rising about 2 inches above the 

 jet showed in the visible part of the spectrum the usual "five- 

 fingered sijectrum." The light from this p.irt of the flame was 

 projected upon the slit. The spectrum contains the water group 

 already described, and in addition a very strong line close to 

 G, and two lines, A 3872 and A 3890 ; this latter hue is seen to 

 be the more refrangible limit of a group of fine lines shading off 

 towards K. 



The ultra-violet group, when carefully compared with the 

 group in the spectrum of pure Jiydrogen, shows several small 



differences. I am inclined to believe that tbe.e is the supposi- 

 tion of a second fainter group. There is strong evidence of this 

 in some spectra of hydrogen taken under other conditions. 

 There is also a broad band less refrangible than the strong line 

 at G, and the light extends from this line on its more refrangible 

 side. 



A double Bunsen burner (Fletcher's form) with a strong blast 

 of air was then fitted up. The spectrum was taken of the in- 

 tense blue flame. It resembles the one last described. All the 

 distinctive features are intensified, and a continuous spectrum 

 and groupings of very fine lines fill up all the intervals between 

 the groups already described, so that there is an unbroken 

 strong spectrum throughout the whole region which falls upon 

 the plate. 



A spirit lamp w as arranged before the slit. The spectrum is 

 essentially tlie same as when coal-gas is burned, but as it is less 

 intense only the strongest lines are seen. The water gi"oup, the 

 strong line at G, and the pair of lines rather more refrangible 

 than K, are seen. Probably with a longer exposure the finer 

 lines would also show themselves. 



The distinctive features of the spectra of coal-gas and of 

 alcohol appear to be connected with the presence of carbon. 



Table of IVave-lengt/is of the Principal Lines of the Spectrum of 

 Water. No. I. 



