February 15. 1894] 



NA rURE 



377 



Remarkable meteors in the night from November 6 to 7, 1893, 

 by the same author. Several striking meteors were observed 

 in various quarters during that night, in the constellations of 

 Pegasus, Ursa Major, and Ursa Minor. The report of the 

 explosion of the last was plainly audible. — On some new pro- 

 cesses for the detection of vegetable and mineral oils, by \V. de 

 la Roycre. An alkaline solution of rosaniline may be used for 

 determining minute quantities of fatty oils mixed with mineral 

 oils. Hall a gramme of fuchsine is dissolved in half a litre of 

 boiled distilled water. A 30 per cent, solution of caustic soda 

 is added drop by drop uniil complete discolouraiion is just 

 obtained. The mixture is then made up to one lure with dis- 

 tilled water, and kept in a well-stoppered bottle. A few drops 

 of this are added to a small quantity of the oil in a porcelain 

 dish, and stirred. The animal and vegetable oils quickly 

 assume a pink colour, and mixtures of these with mineral oils 

 are coloured red with an intensity proportional to the quantity 

 of animal or vegetable oil present. Other coal-tar products, 

 such as picric acid, purpurine, rosolic acid and eosine, show a 

 similar behaviour. 



Inieniationales Archiv fiir Ethnographic, B 1. vi., Heft vi. 

 — This is the last number of the first series of this valuable 

 journal, which has been so excellently published by Heer Trap. 

 The first article, by Schmeltz, on a Dyak and two Japanese 

 swords, is lavishly illustrated by three coloured plates. Baron 

 van Hoevell describes and figures the flattening of the skull and 

 chest in Buool (north coast of Celebes). The chest flattening- 

 board is always employed on the boys, but not always the head- 

 board ; both are always inflicted on the girls, the object being 

 solely for beauty, and to improve the marriage value of the 

 latter. It is not for the purpose of making them clever and 

 active, foi the people themselves say " Reason is the gift of 

 God." Schmeltz adds an appendix, in which he gives the 

 geographical distribution of the custom of skull deformation. 



SOCIETIES AND ACADEMIES. 

 London. 



Royal Society, February l.^-" An Instrument for Grinding 

 Section-plates and Prisms of Crystal- of Ariificial Preparations 

 accurately in the desired directions." By A. E. Tutton. 



By means of this instrument a truly plane surface may be 

 ground and polished in any desired direction in a crystal ac- 

 curately to within ten minutes of arc, in a fraction of the time 

 required for the hand grinding of an approximately true surface, 

 and without danger of fracturing the crystal. It consists 

 essentially of four parts, (i) A rotating horizontal divided 

 circle, within the vertical axis of which two other axes are 

 capable of vertical motion ; the innermost carries at its lower 

 extremity the crystal and its means of adjustment, and the other 

 is connected with a counterpoising apparatus by which the 

 pressure with which the crystal bears upon the grinding disc 

 can he modified according to its relative softness and friability. 

 (2) A series of graduated circular adjusting movements by which 

 the desired direction (plane) in the cr\ stal can be brought exactly 

 parallel to the grinding .-urface. (3) A horizontal collimaior 

 and telescope for goniometrically ob-rrving the crystal. (4) A 

 rotating table carrying a detachable grinding disc of ground 

 glass, and underneath it a p )lishing disc of much more finely 

 ground glass. A special crystal holder is also provided, which 

 enables a second surface to he ground truly parallel to the 

 first. Prisms may be ground with the same facility as section- 

 plates. 



" An Instrument of Precision for producing Monochromatic 

 Light of any desired Wave-length, and its Use in the Investi- 

 gation of the Optical Properties of Crystals." By A. E. Tutton. 



This instrument enables the whole field of an optical instru- 

 ment to be evenly and brightly illuminated with spectrum 

 monochromatic light of any desired wav, length. It has been 

 devised especially for use in coiinecnon with the axial angle 

 polariscopical goniometers, spectrometers, stauroscopes, micro- 

 scopes, and other instruments employed in the investigation of 

 the optical properties of crystals, but is capable of much more 

 extensive application. It was suggesied by the apparatus de- 

 scribed by Abney {/"/z//. Mag. 18S5, vol. XX. p. 172), but differs 

 from that arrangement in most of its deads, and particularly in 

 the employment of a fixed instead of a movable exit slit ; of a 

 rotatory instead of a fixed dispersing a(>paratus, which is capable 

 of accurate graduation for the passage of rays of definite wave- 

 lengths through the exit slit ; and in the manner of utilising the 



NO. 1268, VOL. 49] 



issuing line of monochroma'ic light, which, insteai of being 

 directed upon an opaque whiie screen, is diffused so as to be 

 evenly distributed over the field of an observing instrument 

 when thit instrument is placed directly in its path. 



The instrument resembles a compact spectroscope in appear- 

 ance. The two optical tubes are exactly similar. Each carries 

 a slit, the jikvs of which are made to move equally on each side 

 of the line of contact, and a lens combination of two inches 

 aperture, in order to pass a large am )unt of light. A single 

 prism of heavy flint glass is employeil, of large size and of the 

 highest dispersion compatible with freedom from colour ; it is 

 carried upon a rotating divided circle. Either optical tube may 

 be used as collimator. The other may be converted inio a 

 telescope for the purpose of graduating the instrument by attach- 

 ing an eyepiece in front of the slit ; the knife edges of the latter, 

 which are clearly focussed by the eyepiece, serve as parallel cross 

 wires between which solar or metallic lines may be adjusted by 

 rotation of tlie prism. The readings of the circle for such 

 positions are recorded in a ta ile supplemented by a curve. 

 Upon removal of the eyepiece and illumination of the receiving 

 slit by any sufficiently powerful source of light, monochromatic 

 lijht of any desired wave-'e igth may at once be produced by 

 setting the circle to the reading recorded for that wave-length. 

 The issuing line of coloured light is widened just sufficiently to 

 fill the whole field of the observing instrument by attaching a 

 screen of very finely ground glass, carried in a short tube sliding 

 along a bar, about one inch in front of the exit slit. Upon 

 bringing the optic axial angle goniome er, carrying an adjusted 

 section plate, close up so that the end of the polarising tube 

 almost touches the ground glass, the interference figure is ob- 

 served sharply defined upon a homogeneously coloured and 

 illuminated background. The arrangement is particularly 

 valuable for the study of cases of crossed axial plane dispersion. 

 It is equally adapted for use in the determination of indices of 

 refraction by the methods of refraction or total-reflection, and 

 also in the determination of extinction angles by means of ihe 

 stauro-cope. 



Chemical Society, January 18. — Dr. Armstrong, President, 

 in the chair. — The following papers were read : — The molecular 

 formula; of some liquids as determined by their molecular sur- 

 face energy, by Miss E. Aston and W. Ramsay. The molecular 

 weights of phenol and bromine in the liquid state are somewhat 

 greater than in the gaseous state ; liquid nitric acid has ap- 

 proximately the molecular formula HoN^Og. The molecule of 

 liquid sulphuric acid below 132' has the composition 32H.SO4 ; 

 liquid phosphorus has the normal molecular composition P4. 

 Chloropicrin has the composition CO^i^^-iii- — Contributions 

 to our knowledge of the aconite alkaloids. VIII. On picra- 

 conitine, by VV. R. Dunstan and E. F. Harrison. The 

 " picraconitine," obtained by Groves from the roots of Aconi- 

 tum Napellits is merely impure isaconitine. — Contributions to 

 our knoaledi^e of the aconite alkaloids. IX. The action of 

 heat on aconitine, by W. R. Dunstan and F. H. Carr. On 

 heating aconitine it bieaks up into ace:ic acid and pyraconitine, 

 C3iH4iN'0,„ ; the latter ba-e on hydrolysis yields benzoic acid 

 and pyraconi ine CajHsyNOg. — Contributions to our knowledge 

 of the aconite alkaloids. X. Further observations on the con- 

 version of aconitine into isaconitine, by W. R. Dunstan and 

 F. H. Carr. — Interaction of benzylamine and ethylic chlor- 

 acetate, by A. T. Mason and G. R. Winder. The first product 

 of the action of benzylamine on ethylic chloracetate is benzy- 

 lauiidoaceiic acid ; the latter readily condenses, yielding 

 dibcnzyl-a-7 diacipiperazine. — Condensation products from 

 be zylamine and several benzenoid aldehydes, by A. T. Mason 

 and G. R. Winder. — Constitution of rubiadin, by E. Schunck 

 and L. Marchlewski. The authors assign the following con- 

 stitution formula to rubiadin : — 



O OH 



OH 



O Me 



— The monalkyl ethers of alizarin, by E. Schunck and L. 

 Marchlewski. — Ruberythric acid, by E. Schunck and L. March- 

 lewski. —The colouring matter of the Indian dye-stuff "Tesu," 

 by J. J. Hummel and W. Cavallo. The dye-stuff" " Tesu ' 

 consists of the dried flowers of Biitea frondosa ; the latter con- 

 tain a glucoside which on hydrolysis yields a compound of the 

 formula CigHj405. 



