:qo 



NATURE 



[December 26, 1895 



SCIENTIFIC SERIALS. 



American yotirnal of Scteine, November. — On the wave- 

 length of the D3 helium line, by A. De Forest Palmer, jun. 

 The definition and intensity of this line varied greatly from day 

 to day. The best combination of intensity and definition was 

 obtained by avoiding prominences and working only on very 

 clear days. The average for seventeen series of measurements 

 was 5875-939 ± -006. — Some additional notes on argon and 

 helium, by Edwin A. Hill. The conclusion that argon is 

 monatomic depends upon the correctness of three assumptions, 

 viz., that a gas, with little or no rotational energy, must be 

 monatomic ; that the ratio of the two specific heats of i '67 proves 

 the gas to have no rotational energy ; and that the ratio of the 

 two specific heats is correctly determined. In choosing between 

 the two alternatives of a diatomic gas without rotational energy 

 or a free atom devoid of chemical affinity, the presumption is 

 strongly raised that it is not a monatomic gas, but diatomic and 

 chemically inert because the two atoms of the molecule are very 

 strongly bound together. There is not much doubt that helium 

 is a mixture, and if anything can be argued from the analogies 

 betiveen argon and helium, argon is a mixture likewise. — Recent 

 progress in optics, by W. Leconte Stevens. Part II. This con- 

 cluding portion of the presidential address deals with colour 

 photography, with recent researches on the spectrum and on 

 polarised light, and with colour sensation. — Effect of the mutual 

 replacement of manganese and iron on the optical properties of 

 lithiophilite and triphylite, by S. L. Penfield and J. H. Pratt. 

 The transition from LiMnP04 to LiFeP04 is marked by a con- 

 siderable change in the optical characters of these isomorphous 

 minerals. With an increase in iron there is an increase in the 

 indices of refraction, and also the divergence of the optical axes 

 changes rapidly. — The reduction of selenic acid by hydrochloric 

 acid, by F. A. Gooch and P. S. Evans, jun. A solution of 

 selenic acid is boiled in hydrochloric acid, and if the solution is 

 not too dilute the reduction is obtained in a few moments. The 

 hydrochloric acid must form at least 30 per cent, of the entire 

 solution. The solution should be boiled until all th? chlorine 

 is expelled, but must not be allowed to fall below two-thirds of 

 its original volume. — Reduction of selenic acid by potassium 

 bromide in acid solution, by F. A. Gooch and W. S. Scoville. 

 When intermixed with sulphuric acid and potassium bromide, 

 selenic acid liberates bromine in proportion to the excess of acid, 

 the bromide, and the elevation of the temperature. On boiling, 

 the bromine is evolved and may be collected in potassium iodide, 

 and the iodine thus set free may be determined by standard 

 sodium thiosulphate and taken as the measure of the bromine 

 distilled. — Restoration of some European Dinosaurs, with sug- 

 gestions as to their place among the Reptilia, by O. C. Marsh. 

 The geological positions of Compsognathiis and Scelidosaurus are 

 fully determined, but that of Hypsilophodon and Igiianodon is not 

 so clear. The latter are found in the Wealden, which is usually 

 considered to be Cretaceous, but might as well be classified as 

 Upper Jurassic. 



The numbers of the Joitrnal of Botany for November and 

 December are chiefly occupied with papers on descriptive botany. 

 Mr. D. Prain completes his account pf the genus Argemone, and 

 Herr R. Schlechter his Asckpiadacece Elliotiana, and describes 

 also two new genera of the order, from Madagascar and from 

 Angola. 



SOCIETIES AND ACADEMIES. 



London. 



Royal Society, November 21. — "On the Gases obtained 

 from the Mineral Eliasite." By J. Norman Lockyer, C.B., 

 F.R.S. (Received August 6, 1895.) 



Observations have been made of the gases obtained from 

 the mineral eliasite heated in vacuo, in the manner which I have 

 described in a former paper,i and, in addition to lines of known 

 gases, others Jiave been noted, for which no origins can be traced, 

 at the following wave-lengths : — 



Angstrom. 

 6121-4 



6064 -6 

 5990-2 

 5874-9 

 5845-7 

 5428-8 

 5403-1 



Rowland. 

 6122-4 

 6065-7 

 5991-2 

 5875-9(03) 

 5846-7 

 5429-8 

 5404- 1 



NO. 



1 Roy. Soc. Proc, vol. Iviii. p. 68. 



1365, VOL. 53] 



The wave-lengths of these lines have been determined by 

 means of a Steinheil spectroscope having four prisms, compari- 

 sons being made with adjacent metallic lines, and the positions 

 interpolated by micrometric measurements ; the accuracy may 

 perhaps be taken to be within O'l tenth metres. Other lines 

 have been noted, but they are not included in the list, for the 

 reason that their wave-lengths have not yet been determined 

 with the dispersion stated above. 



Of the lines in the foregoing list, six are in all probability 

 coincident with chromospheric lines, as shown in the following 

 table, which also indicates the frequencies and brightnesses of 

 the lines according to Young : — 



It IS important to point out that all these lines do not appear 

 in the spectrum at the same time. For instance, in the first two 

 specimens of the mineral no trace of D3 was noted, but in the 

 third portion examined, all coming from the same specimen, D3 

 appeared as a pretty bright line. Again, as in the case of a 

 previous operation on brtiggerite,^ in one experiment with eliasite 

 the products of distillation, collected in four stages, gave different 

 spectra. 



These facts seem to indicate that the gas obtained from eliasite 

 is either a compound or a mixture of gases, just as is that 

 obtained from broggerite according to former experiments. 



It is also to be remarked that among the lines in the 

 eliasite spectrum, those at 6122-4 and 6065-7 have been recorded 

 in the gases obtained from cleveite, and 6122-4 has also been 

 noted in the gas obtained from gummite. 



It seems to be more than probable, therefore, that the lines 

 observed in eliasite indicate a new gas, in some way associated 

 with those given off by cleveite and broggerite, and the fact that 

 D., is not necessarily present in the spectrum, furnishes an 

 additional argument in favour of the view that the gas obtained 

 from cleveite or broggerite is complex. 



Addendum. Received November 18. 



The results in the foregoing paper depend upon eye oKserva- 

 tions on the red end of the spectrum. Since it was communi- 

 cated to the Society the blue end has been investigated photo- 

 graphically. Many specimens of eliasite have been distilled, 

 and numerous photographs of the spectra of the gases given off 

 have been taken. 



The work has been rendered difficult by the very small quan- 

 tity of what I believe to be a new gas, and the large quantity of 

 carbonic acid, nitrogen, and hydrogen given off from Ihe mineral. 

 Attempts have been made to get rid of the known gases, in order 

 to make the lines in the new gas better visible, and then the 

 amount of gas was in most cases very small and at times ad- 

 mixed with argon produced by the sparking. 



The photographs have been measured and reduced, and it is 

 probable that the lines, or some of them, which cannot be 

 ascribed to any known gases, may belong to the same gas as that 

 giving the lines observed in the red. I append a table of some 

 of these lines, which suggest possible coincidences in stellar and 

 solar spectra ; the numbers in brackets indicate the intensities of 

 the lines, 6 being the maximum in the case of o Cygni, and 10 

 the maximum in the case of the eclipse spectrum. 



Wave-lengths 



(Rowland). Coincidences. 



3961-4 o Cygni (6) 



4035-2 Eclipse (2) 



4058-6 „ (I) 



a Cygni (3) 



„ (3) 



4224-0 Eclipse (i) 



4255-7 " (I) 



4442-5 — " (3) 



1 Roy. Soc. Proc. vol. Iviii. p. 194. 



4128-31"." 

 4131-4/ ... 



