ii6 



NATURE 



{pec.b, 187;^ 



£cre V, by which it can be separately raised or laweied ; and by 

 means of another screw the small brass plate holding the sus- 

 pending screws can be raised or lowered as a whole. A few 

 numerical results were given to illustrate the action of the appa- 

 ratus. These were taken from a set of experiments in which the 

 difference of potential needed to produce sparks in air between 

 two equal brass spheres of 2 '61 cm. radius was measured. The 

 following are the results for a; Jew of the shortest and longest 

 sparks measured : — 



Length of Spark. 



0*1325 

 0-1825 

 0-237 



0-68 

 0-71 

 074 



Difference of Potential. Mean Electrical Force. 



17-4 

 20-4 

 24-5 



62-9 

 65-2 



68-7 



131 



117 

 104 



93 

 92 



93 



Vienna 

 Imperial Academy of Sciences, October ri. — Preliminary 

 note on the position of the optical axes of elasticity in gypsum 

 for various colours, by M. Lang, The angle of the optic 

 axes shows a maximum for the Fraunhofer line D. The 

 dispersion of the axes of elasticity in the plane of symmetry is 

 abnormal. These observations agree on the one hand with 

 Poggendorfif' s exact description of the axial forms of gypsum, 

 and on the other side with Descloigeaux's observation that at 

 the higher temperatures, where the plane of axis is at right- 

 angles to the place of symmetry, no horizontal dispersion is 

 observable. — Annual periods of the insect fauna of Austro- 

 Hungary, by M. Fritsch. — On the relation between the second 

 principal proposition of the mechanical theory of heat and 

 the calculation of probability respecting the propositions on heat- 

 equilibrium, by M. Boltzn.ann. — The cylindroid and its spe- 

 cialties, by M. Kozak.— Simple calculation of elliptic arches, 

 by G. Seewald. — On eruptive sands, and on the Flysch and the 

 Argille scagliose, by M. Fuchs. — On equal figures in curves, 

 cones, and surfaces of the second order and of certain of higher 

 orders, by M. Puchta. — Calculation of cylindrical vessels with 

 complicated relations, by M. Streicher. — On development of the 

 resinous passages in some coniferge, by M. Weiss. — Continued 

 studies on the mode of ending of nerves of smell, by M. Exnor. 



Paris 



Academy of Sciences, November 26.— M. Peligot in the 

 chair : — The following papers were read : — Geographical posi- 

 tions of the principal points of the coast of Tunis and Tripoli, by 

 M, Mouchez. This relates to observations during the hydro- 

 graphic voyage of the Castor in 1876, of some fifty points equally 

 distributed along about 300 leagues of coast. — On some applica- 

 tions of elliptic functions (continued), by M. Hermite. — The 

 Echidna of New Guinea, by M. Gervais. He notes several 

 points in which the head differs, from that of the Australian 

 animal. — On invariants, by Prof. Sylvester. — On the waves of 

 various kinds which result from the working of the sluice of 

 Aubois, by M, Caligny. — On the solution of the equauon of the 

 fifth degree, by M. Brioschi. — Nature of the hydrocarbons pro- 

 duced by action of acids on manganesiferous spiegeleisen, by M. 

 Cloez. Several of these products seem identical with those which 

 exist in the ground and are extracted on a large scale under the 

 name of petroleum. This production of complex carbonised 

 compounds, without any intervention of life, supports the views 

 of certain geologists on the origin of petroleum. The reproduc- 

 tion of a large number of organic species might be realised tiy com- 

 mencing with ethylenic or formenic hydrocarbons, furnished by 

 cast iron. — Discovery and observation of the planet 175 by Mr. 

 Watson. — On the distances of stars, by M. Flammarion. He 

 cites several facts which seem not to allow of basing on differ- 

 ences of brightness an estimate of dit^tances. — On the interme- 

 diary integral of the third order of the equation with partial 

 derivatives of the fourth order expressing that the problem of 

 geodesic lines supposes an algebraic integral of the fourta degree 

 by M. Levy. — Graphic tables and anamorphic geometry j recla- 

 mation of priority, by M. Lalanne. — Second note on the mag- 

 netisation of steel tubes, by M. Gaugain. The variations of 

 magnetism produced by heat in a solid bar of steel ar« not 



different icova. those in a system composed of a tube and a core. 

 Both seem to depend on the inverse magnetism developed by 

 the mutual reaction of concentric layers, whether of the bar or 

 of the system. — Liquefaction of bioxide of nitrogen, by M. 

 Cailletet. This he effected by compressing to 104 atmospheres 

 at — 11°. At + 8° the bioxide is still gaseous under 270 

 atmospheres. He hopes, also, to be able to liquefy formene. 

 M. Berthelot remarked on the importance of this achieve- 

 ment, and thought it probable that most of the gases not 

 yet liquefied, such as oxygen, which already diverges from 

 Mariotte's law under great pressures, and oxide of carbon, would 

 yield to M.'Cailletet's new processes. — On nitrification by organic 

 ferments, by MM. Schloesing and Muntz. Whenever, in these 

 experiments, a nitrifiable medium has remained in the presence 

 of chloroform, or has been heated to 100°, then guarded from 

 dust, the nitrification has been suspended, but it has been 

 possible to renew it, by introducing into the heated medium a 

 minimum quantity of a substance like mould in process of nitrifi- 

 cation. — On the termination of the nerves in tactile corpuscles, by 

 M. Ranvier. He studied these organs in the tongue and bill of 

 the domestic duck (where they are found in great simplicity). 

 The tactile disc, the true sensitive nervous organ, is protected 

 against mechanical excitations from without by the special cells 

 surrounding it. It can only be impressed in an indirect way. — 

 An experiment in stasimetry or measurement of the consistence 

 of organs, by M. Bitot. The instrument is a kind of balance 

 having at the end of one arm a perforating or sounding needle, 

 at the end of the other a small controlling plate, and at the centre 

 a pendulum with successive weights and a long indicator needle 

 connected to it above, moving over a graduated scale. — On a mo- 

 dification of Bell's telephone, with multiple membranes, by M. 

 Trouve. A cubical chamber is substituted for the single mem- 

 brane ; each face of it is a membrane which, in vibrating, influences 

 a fixed magnet with electric circuit. Associating all the currents 

 generated, an intensity is obtained proportional to the number of 

 magnets affected; — On the telephone, by M. Pollard. This 

 describes some experiments at Cherbourg. M. Du Moncel 



called attention to the ideas expressed by M. Ch. B more 



than twenty years ago, and which contains the telephone in 

 germ. — On a new sounding apparatus for works of coast hydro- 

 graphy, by M. Pinheiro. 



CONTENTS Page 



Technical Education 97 



North American Starfishes 9^ 



Vogel's "Spectrum Analysis." By Dr. Arthur Schuster . . 99 

 Our Book Shelf :— 



Young's "Nyassa; a Journal of Adventures whilst Exploring 

 Lake Nyassa, Central Africa, and Establishing the Settlement of 



' Livingstonia ' " 99 



Cayzer's "Britannia: a Collection of the Principal Passages in 



Latin Authors that refer to this Island " 99 



Letters to the Editor : — 



The Colour Sense of the Greeks.— ReV. W. Robertson Smith . iod 

 Ihe Comparative Richness of Faunisand Floras tested Numeri- 

 cally. — Alfrbd R. Wallace ico 



Mr. Crookes and Eva Fay.— Alfred R Wallace 101 



Nocturnal Increase of Temperature with Elevation. —Dr. E. 



Bonavia 10 ' 



Expected High Tides —B. G. Jenkins loi 



Diffusion Figures in Liquids —C Tom LiNSON, F.R S 102 



Bees and Flowers — John B. Bridgman 102 



Hearing in Insects. —Henry Cecil 102 



A Zoological Station for the Channel Islands. By W. Saville 



Kent i°3 



German Universities 1^3 



Our Astronomical Column : — 



The Meteorite of July 20, i860 104 



The Planet Mars and B. A. C. 8129 loS 



The Binary star Ca^tor 105 



Transits of the Shadow of Titan across the Disc of Saturn . . . 105 



The " Nautical Almanac," i83i 103 



Ole RoMER. By Dt.'^. DoBKKQK. (With Illustrations) .... 105 



Notes '^°^ 



The Liberty of Science in the Modern State, IIL By Prof. 



Rudolf Virchow ^'^ 



American Science "3 



The Meteor "3 



University AND Educational Intelligenck "4 



SOCIKTIKS AND AcADBMIBS . .1 , .... "5 



