May .16, 1889] 



NATURE 



71 



to irregularities in the upper surface of the negative. Dr. Glad- 

 stone said he was not satisfied with Prof. Stokes's nitrous oxide 

 explanation, but thought the plienomenon may be due to some 

 kind of reversion. He also mentioned that a negative might 

 probably be obtained from Mr. Shephard, of Westbourne Grove. 

 As regards multiple flashes, Mr. Boys said he had often seen 

 seven or eight flashes traverse the same path in rapid succession. 

 On the motion of the President, the discussion was adjourned 

 until the next meeting, when Mr. Whipple hopes to exhibit the 

 negative referred t >, together with photographs of his experi- 

 mental dark flashes. — On quartz as an insulator, by Mr. 

 C. V. Boys, F.R.S. In making quartz fibres the author ob- 

 served that the ends of fibres broken during the shooting process 

 coiled up into screws, and projected themselves against anything 

 brought in their vicinity. After a short time they released them- 

 selves and sprang back to their original position. This could be 

 repeated indefinitely, and the only explanation he could think of 

 was that the fibre was electrified. If so, then to exhibit such 

 phenomena the insulating qualities of quartz must be very great, 

 and experiments were shown to demonstrate this deduction. A 

 small pair of charged gold leaves were suspended from a short 

 quartz rod in a moistened atmosphere, and the deflection fell one- 

 quarter the original amount in about five hours. A clean glass 

 rod under the same conditions would discharge the leaves in a 

 few seconds. Dipping the quartz into water did not seem to 

 diminish its insulating properties, and ordinary chemicals pro- 

 duced no permanent prejudicial effect. The author considers 

 that quartz will be very useful in electrostatic apparatus, for the 

 troublesome sulphuric acid may be dispensed with. — On a re- 

 fraction goniometer, by Mr. A. P. Trotter. The goniometer, 

 which was designed when determining the figure of a refracting 

 surface to effect a special distribution of light, is practically a 

 movable four-bar linkwork, representing the figure given in 

 Deschanel (p. 924) ; two of the bars are parallel to the incident 

 and emergent rays, and the other two normals to the faces of the 

 prism. By its means the angle of a pri-m to jiroduce a given 

 deviation, when the index of refraction and angle of incidence 

 are known, can be readily found. A series of curves expressing 

 the relation between incidence and deviation for prisms of various 

 angles were shown, and the same curves show the minimum 

 deviation and limiting angle for prisms of all angles represented. 

 The author thinks the instrument will be useful in physical 

 laboratories for adjusting optical apparatus and for the calculation 

 of lighthouse and other polarized lenses, Fresnel pris us, &c. 

 Prof. Herschel said he found a wooden model illustrating the 

 relations between the angles of incidence and refraction very 

 useful in teaching ; and Mr. Blakesley sketched an arrangement of 

 links and cords devised for the same purpose. Mr. Boys con- 

 sidered that all such relations were best seen on a slide rule. — 

 A note on apparatus to illustrate crystal forms, by Prof. R. J. 

 Anderson, was read by Prof. Perry. Th£ apparatus is con- 

 structed of cords, pulleys, and weights arranged to produce the 

 required figure when in equilibrium. By increasing or decreasing 

 some of the weights the corresponding axes of the crystal forms 

 can be lengthened or shortened, and the passage from one 

 system to another effected. In one arrangement the forces may be 

 divided or united, and the pulleys are carried by rings capable 

 of rotating on different axes. By this apparatus the various 

 conditions are said to be beautifully illustrated, and methods of 

 deriving the oblique from the rectangular systems are shown in 

 photographs which accompany the paper. 



Entomological Society, May i. — Mr. Frederick Du Cane- 

 Godman, F.R.S., Vice-President, in the chair. — Mr. W. L. 

 Distant announced the death of Dr. Signoret, of Paris, one of 

 the Honorary Fellows of the Society. — Dr. Sharp exhibited 

 male and female specimens of Rhomborhina japonica, in which 

 the thorax was abnormal ; also, a specimen of Batoccra roylei, 

 which he had kept in a relaxed condition in order to be able to 

 demonstrate the power of stridulation possessed by this species. 

 — Dr. N. Manders exhibited a small collection of Coleoptera, 

 including several remarkable and very interesting species, re- 

 cently made by him in the Shand States, Burmah. — Mr. C. O. 

 Waterhouse exhibited, for Mr. Frohawk, a series of wings of 

 British butterflies, prepared in accordance with a process (de- 

 scribed by Mr. Waterhouse in the Proc. Ent. Soc, 1887, p. 

 rxiii.'), by which they were denuded of their scales so as to 

 pxjiose the neuration. — Dr. P. B. Mason exhibited cocoons of 

 species of spider — Theridion pallens. Black., — from Cannock 

 ^hase, distinguished by the presence of large blunt processes on 

 "leir surface.— Mr, H. Goss exhibited, for Mr. N. F. Dobree, 



a number of scales of Coccidce, picked off trees of Acacia melan- 

 oxylon and Grevillea rohusta, growing in the Market Square, 

 Natal. These scales had been referred to Mr. J. W. Douglas, 

 who expressed an opinion that they belonged to the family 

 Brachyscelidiv, and probably to the genus Brachyscelis, Schrader. 

 He said that most of the species lived on Eucalyptus. — Captain 

 H. J. Elwes exhibited a long and varied series of specimens of 

 Terias hecabe. He remarked that all the specimens which had 

 strongly defined markings were taken in the cold and dry season, 

 and that those which were without, or almost without, markings, 

 were taken in the hot and wet season ; further, that he believed 

 that many specimens which had been described as distinct were 

 merely seasonal forms of this variable species. Mr. W. L. 

 Distant, Mr. F. D. Godman, F.R.S., Prof. Meldola, F.R.S., 

 Mr. H. T. Stainlon, F. R. S., and Mr. G. Lewis took part in 

 the discussion which ensued. — Mr. H. Burns exhibited, and 

 made remarks on, a number of nests of living ants of the fol- 

 lowing species, viz. Formica fusca, Lasius alienus, L. flavus 

 L. niger, Mynnica ruginodis, M. scabrinodis, Sec. One of the 

 nests contained a queen of L. flavus, which had been in the 

 exhibitor's possession since September 1882. — Mr, W. Darinatt 

 exhibited specimens of Thaumantis hoivqua, West., from Shang- 

 hai. — Mr. G. C. Bignell communicated a paper entitled "De- 

 scription of a New Species of British Ichneuvtonidce." — Mr. A, 

 G. Butler communicated a paper entitled "A Few Words in 

 reply to Mr. Elwes's statements respecting the incorporation 

 of the Zeller Collection with the General Collection of Lepi- 

 doptera in the Natural History Museum." Captain Elwes, Mr. 

 Siainton, Mr, Godman, and others, took part in the discussion 

 which ensued. 



Paris. 



Academy of Sciences, May 7. — M, Des Cloizeaux, 

 President, in the chair. — On elliptical polarization by vitreoUs 

 and metallic reflection ; extension of the methods of observation 

 to the ultra-violet radiations, by M. A. Cornu. The principles 

 on which Cauchy has established the theory of these two orders 

 of phenomena and the form of the laws controlling them differ 

 so greatly that most physicists regard them as essentially dis- 

 tinct. But these experiments show that this is not the case, and 

 that the same substance may present a continuous transition from 

 one to the other according to the nature of the reflected radia- 

 tion. It follows that the phenomena presented by transparent 

 substances with metallic sheen (fuchsine, platinocyanides, &c.), 

 far from being exceptional, merely constitute particular forms of 

 the general phenomenon of reflection. — On the origin of bronze, 

 by M. Berthelot. The author has analyzed specimens from a 

 statuette from Tello in Mesopotamia, and from the sceptre of the 

 Egyptian king Pepi I. (sixth dynasty), both dating back to 

 about 4000 B.C., and both consisting of pure copper. From 

 this he argues that, as in the New World, the Stone Age was 

 followed by a Copper Age in the eastern hemisphere, anl that 

 the bronze period cannot bs more than some fifty or sixty cen- 

 turies old. — On the thionic series ; action of the alkalies, by M. 

 Berthelot. Having already determined the heats of formation 

 of the thionic compounds {Comptcs rendus, cviii. p, 773), the 

 author here deals with the reciprocal transformations of these 

 compounds under the influence of the alkalies. The penta- 

 thionates, tetrathionates, an I trithionates are treated in detail, 

 and it is concluded that these as well as other compound 

 substances, such as metaphosphoric and pyrophosphonc acids, 

 hitherto regarded as isolated and exceptional, all come within 

 the same general theories as the organic acids. — Note on an iron 

 meteorite discovered buried in the ground at Haniet-el-Beguel in 

 Algeria, by M. Daubree. This meteorite, found at a depth of 

 5 metres, while sinking a well in the Wed Mzab district, appears 

 to be of great age, having fallen probably during the 

 Quaternary epoch. It shows the Widmanstatten figures quite 

 distinctly, and its other characteristics place its extra-terrestrial 

 origin beyond all doubt. — Remarks accompanying the presenta- 

 tion of the third part of the Bulletin international de la Carte du 

 Ciel, by M, Mouchez. In these remarks special attention is 

 called to Mr, Isaac Koherts's panto^raveur stellaire, an ingenious 

 and valuable process, by means of which the photographic im- 

 pressions of the stars can easily be transferred to metallic plates, 

 and thus preserved from all danger of perishing. The method 

 is simple and economical, and allows of an unlimited number of 

 copies being taken for general use. By this invention all risk is 

 removed of the labours of the International Association for photo- 

 graphing the Heavens being lost to future generations, — Researches 

 on the application of the measurement of rotatory power to 



