June 27, 1907] 



NA TURE 



215 



Mineralogical Society, June ii. — Piof. H. A. Mierp, 



F.R.S., president, in the chair. — Hamlinite from the 

 Binnonthal : H. L. Bowman, A mineral ocriirring in 

 small brown six-sided plates in the white dolomite, to 

 which the name bowmanite was given by Mr. Solly in 

 1904, is shown by analysis to be identical with hamlinite. 

 The crystals .show a division into si.x biaxial sectors, and 

 are consequently pseudohexagonal. — Faceted beads of zinc : 

 T. \'. Barker. The president described beads of zinc 

 deposited on crucible lids by .sublimation of zinc through 

 oxide of tin. Some of these beads are covered with 

 brilliant facets, and present the appearance of crystals 

 rich in faces. Mr. Barker has found that they do not lie in 

 zones or obey the laws of distribution of ordinary crystal 

 faces, and cannot therefore be regarded as the faces of a 

 single crystal. There is, however, no evidence, from etch- 

 ing by acid, that the bead is an aggregate of crystals. 

 The nature of these remarkable faces is difficult to under- 

 stand. A bead of platinum presenting the same peculiari- 

 ties was measured by the late Prof. Miller. — Chlor- 

 manganokalite : Dr. Vl. J. Johnston-Lavis and L. J. 

 Spencer. A preliminary account of this new \'esuvian 

 mineral was given by Dr. Johnston-Lavis in Natl'Re on 

 May 31, 1906. K new analysis of the mineral gives the 

 formula MnCI..4KCl. The crystals are rhombohedral with 

 a rhombohedral angle of 57° 36' ; they are optically 

 uniaxial with very weak positive birefringence; the re- 

 fractive index is 1-59 and the specific gravity 231. — Mr. 

 L. J. Spencer exhibited a suite of beautifully crystallised 

 minerals, presented to the British Museum by Mr. Percy 

 C. Tarbutt, from the Rhodesia Broken Hill mines in 

 north-western Rhodesia. In driving a tunnel through one 

 of the kopjes, which consist mainly of cerussite and 

 hemimorphite, a cavern containing flint implements and 

 bones of recent mammals was encountered, and a cavity 

 in the bone-breccia on the floor of this cave was encrusted 

 with magnificent groups of hopeite crystals (the rare 

 hydrous zinc phosphate discovered by Sir David Brewster 

 in 1823). In the vicinity of the cave, crystals of another 

 hydrous zinc phosphate were found in association with 

 descloizite (hydrous vanadate of lead and zinc). The 

 crystals of this new species, for which the name tarbuttitc 

 is proposed, are anorthic ; they possess a perfect cleavage 

 in one direction, through which .efnerges obliquely the 

 acute negative bisectrix of the optic axes. Cavities in the 

 ordinary ore are lined with large twinned crystals of 

 water-clear cerussite, which are encrusted with small 

 crystals of hemimorphite. — .A group of quartz crystals from 

 British Guiana was exhibited by Mr. Andersoni and a 

 fine crystal of apatite by Mr. Gordon. 



Mathematical Society, June 13. — Prof. W. Burnside, 

 president, in the chair. — The number of representations 

 of a number as a sum of 2r squares, where 2r does not 

 exceed 18: Dr. J. W. L. Glaisher. — .^n extension of 

 Eisenstein's law of reciprocity : A. E. Western. — Note 

 on a special set of classes of partial differential equations 

 of the second order : Prof. A. R. Forsyth. — Various 

 extensions of -Abel's lemma: Prof. T. J. I'.A. Bromvwich. 

 — The arithmetical nature of the coefficients of linear sub- 

 stitutions, third paper: Prof. W. Burnside. — The in- 

 variants of the quintic : Dr. H. F. Baker. — Informal 

 communications were made as follows : — Certain singular 

 points of surfaces : A. B. Basset. — The minimum neces- 

 sary postulates as to a function to be defined as analytic 

 over a region : Prof. E. B. Elliott. 



Royal Astronomical Society, June 14. — Mr. H. F. Newall, 

 president, in the chair. — The inclination of binary star 

 orbits to the Galaxy : Prof. H. H. Turner and T. Lewis. 

 — The illumination of the field of view, and its effect on 

 observations with a transit instrument : Sir W. Christie 

 and H. Christie. — The spectrum of Mira Ceti, as photo- 

 graphed at Stonyhurst College Observatory : Rev. W. 

 Sidgrreaves. The photographs were taken during the late 

 maximum, from December i, 1906, to January 3, 1907, 

 with a Thorp objective prism and with a Hilger com- 

 pound prism. The spectra were compared with that of 

 the star during the previous maximum of 1897-8. The 

 absorption spectrum was substantially the same, but the 

 bands were much weaker in 1906, quite sufficiently so to 

 account for the verv bright maximum. — The origin of 



NO. 1965, VOL. 76] 



certain bands in the spectrum of sun-spots : A. Fowler. 

 The bands are hazy lines, which had not hitherto been 

 traced to their source, various experiments made in 1905-6 

 having given entirely negative results. The author, how- 

 ever, had lately found that many of the bands are part 

 of a fluted spectrum, and can be accounted for by the 

 presence in the umbrEe of spots of a compound of mag- 

 nesium and hydrogen (magnesium hydride). The identifi- 

 cation appeared extremely probable from a comparison of 

 visual observations, but is rendered quite certain by refer- 

 ence to the admirable photographs taken by Prof. Hale 

 at the Mount Wilson Observatory. The identification sup- 

 ports the view that the vapours in spots are at a relatively 

 low temperature. — Account of the instruments and work 

 of the Mount Wilson Observatory, California : Prof. G. E. 

 Hale. A large series of slides was shown on the screen, 

 including spectroheliograph pictures of the solar surface 

 taken in calcium and hydrogen light, comparison of which 

 led to important conclusions as to the relative height of 

 the flocculi. It was suggested that the areas of the flocculi 

 should be systematically measured, and that they might 

 furnish data for determination of the solar rotation. A 

 series of photographic spectra of sun-spots was also shown. 

 Prof. Hale stated that he had found that the heat of the 

 sun caused an actual bending of the mirror employed, the 

 front side becoming convex and the rear side concave. 

 He proposed to obviate this disadvantage by employing 

 mirrors of exceptional thickness, a 17-inch mirror being 

 under construction which is as much as 13 inches thick. 

 Other modifications in the instrumental equipment are 

 also in progress. 



Paris. 

 Academy of Sciences, Jone 17.— M. Henri Becquerel in 

 the chair. — The question of the origin of the lunar seas : 

 MM. Loewy and Puiseux. The hypothesis of the form- 

 ation of the lunar seas by external collisions is discussed 

 and shown to depend upon very uncertain hypotheses, and 

 even then is, taken alone, insufficient to account for all 

 the facts. — The usual mode of publication of equatorial 

 observations and on a means of improving it : G. 

 Bigourdan. — Further remarks on the obliteration of the 

 pleural cavity of elephants : Alfred Giard. Referring to 

 a recent note on this subject by G. Vasse, the author re- 

 marks that the mere fact of the lungs separating easily 

 is no proof of the existence of a pleural cavity, and quotes 

 recent observations by .Schmaltz, Rugc, and Chapman to 

 support his point. — The preparation of anhydrous lithium 

 mo.xoxide : M. de Forcrand. None of the methods 

 previously used for preparing this substance gives a pure 

 product. Purified lithium hydroxide, placed in a platinum 

 or silver boat, is heated to 780° C. in a current of dry 

 hydrogen. The conversion into Li,0 is complete in one 

 hour. — A new method of diagnosis of tuberculosis in man 

 by the tuberculin ophthalo-reaction : A. Calmette. One 

 drop of a sterilised i per cent, aqueous solution of 

 tuberculin is placed in the eye. .\fter five or six hours, 

 conjunctivitis, accompanied ■ by copious secretions, becomes 

 apparent in the tuberculous subjects. In non-tuberculous 

 subjects the tuberculin is without effect. The author 

 suggests the use of this in clinical work as a means of 

 diagnosis, as the reaction is prompt, and neither pain 

 nor permanent ill effects result. — Observations of the 

 Daniel comet (1907^) made with the coude equatorial of 

 the Observatory of Lyons : J. Guillaume. — Observations 

 of the Giacobini comet (19071:) made with the coude equa- 

 torial at the Observatory of Lyons : J. Guillaume. This 

 comet is of thirteenth to fourteenth magnitude. — A new 

 method for resolving several problems on the development 

 of an arbitrary function in infinite series : W. &tekU>fr. 

 — The sutfaces' engendered by a circular helix ; M. Barr^. 

 — The mechanical integration of the hodograph : L. 

 Filloux. — The displacement of the absorption bands of 

 crystals under the action of variations of temperature : 

 Jean Becquerel. The bands of tysonile, parisite, and 

 monazite are all displaced in the direction of the smaller 

 wave-lengths when the temperature is lowered ; in .xeno- 

 time, however, a large number of bands move in the 

 opposite direction. — A new method for the production of 

 flame spectra of metallic bodies : G. A. Hemsalech and 

 C. de Watteville. The air supplied to the louder part 

 of a Bunsen burner carries some of the metal in .i fine 



