July 25, 1895] 



NA TURE 



309 



sufficient and necessary that uncompensated differences of in- 

 tensity exist. — Influence of gases in solution upon the silver 

 voltameter, by John E. Myers. (See p. 276). — The aureole and 

 stratification in the electric arc, and in discharges in rarefie<l 

 gases, by (). Lehniann. The appearance of the electric 

 arc with horizontal carbons is that cjf two gas jets burning 

 against each other, and flaring vertically upwards. This 

 is due to (he currents of hot air ascending between Ihem, 

 and is the same as if the carbons were joined by a white- 

 hot wire. There is no fundamental difi'erence Iwlween 

 the arc and discharges in rarefied gases, as may be shown by 

 taking very small terminals or very large discharge vessels for 

 ihe latter. That the current travels not only through the arc 

 proper, but also through the surroimding "aureole," may be 

 proved by approaching a magnet, which bends the aureole 

 aside. — Magnetisni of asbestos, by L. Bleekrode. The grey 

 variety of asbestos is highly magnetic. Strips of so-called 

 asbestos paper 4 by 3 cm. are attracted at I cm. distance by an 

 electromagnet capaijle of carrying 5 kgr., and fibres of pure 

 asbestos attract .small particles of the .same substance. Asbestos 

 should only be used with great care in sensitive magnetic 

 instruments. 



liullclin dc r Acad^mii Koyale de Belgiijue, No. 4. — On the 

 specific heat of peroxide of hydrogen, by \V. Spring. The 

 method of cooling was employed, and aqueous solutions of 

 various strengths were experimented upon. .\ 74 per cent, 

 solution gave the value o"6893, which fell to 0'6739 at 71 per 

 cent., 0'6276 at 60 per cent., and o'62o8 at 34 per cent. On 

 further dilution to 31 per cent, the specific heat rose again to 

 o 8065. Peroxide of hydrogen thus behaves ver)' much like a 

 solution of alcohol. Chemical decomposition probably exerts 

 a strong influence upon the values at high concentrations, and 

 0'62o8 nnist be taken as a superior limit. Woestyn's law- 

 would give o'6840. Hence it follows that the internal work of 

 hydrogen peroxide must be less than that of water. — On meta- 

 geometry and its three subdivisions, by P. Mansion. The 

 author gives a sketch of a system of geometry of n dimensions, 

 by which the three varieties, those due to Euclid, Riemann, and 

 I^jbatchevski, respectively, can be deduced from elementary con- 

 siderations. The theorem that a straight line, two of whose' 

 points lie in a plane, lies in that plane altogether, applies to all 

 the varieties. But Riemann's geometry is characterised by the 

 proposition : If, in a plane, two straight lines which intersect in 

 a point A also intersect in a second point B, all straight lines 

 pa.ssing through A will also cut the line .\ B a second time. If 

 the sum of the three angles of a .single triangle is etjual to two 

 right angles, the same applies to all triangles, and the space will 

 be Euclidean. In Riemann's curved space this sum is greater, 

 and in Lobatchevski's curved space it is less than two right 

 angles. — On the period of frost extending from January 27 to 

 Eebruary 17, 1895, by A. Lancaster. This amount of frost is 

 imprecedented since 1S38, when the mean of the minima for the 

 da\s between January 8 and 27 was - 1 3° '4 C. at Brussels. This 

 year the mean was - II"C. The isothermals of mean tempera- 

 tures during this period for Belgium show maxima of frost on Ihe 

 frontier'ofLimburgand north of Ha-sselt, the least cold being along I 

 an isothermal of - 5'pa.ssingalong the coast through Ostende. — 

 (Jn a silicate which probably constitutes a new mineral species, by 

 (f. Cesaro. This mineral, which accompanies hexagonite (a violet 

 manganiferous tremolite), comes from .St. I-awrence County, 

 N.\'. It is colourless, or a delicate opaline-jjink. Its hard- 

 ness is 45. It crystallises in the orthorhouibic system, and 

 presents two cleavages along iw'o planes of symmetr}-. Hitherto 

 it has probably been taken for enstatite, but it is distinguished 

 from this by the sign of its bisectrix, by the absence of well- 

 defined prismatic cleavages, by its fusibility before the blowpipe, 

 and by ils angles. Krom anlhophyllite it is distinguished by the 

 absence of inm. — Lunar topogiaphical measurements taken on 

 jihotographs, comparetl with the records of Lohrman and 

 .Madler, by W. Prinz. A table is given of twelve craters near 

 the centre of the di.sc, with the values of their diameters from 

 Ihe maps and photographs. The greatest diflerence between 

 the two cartograijhers appears in the case of Ptoleni;eus, whose 

 crater is given 21,518 m. bn ader by .Miidler than by Lohrmann, 

 and the latter observer is confirmed by the photographs. 



Ihilliliii df r.-lcadi'mie Koyak dc Bilgii/iie, No. 5. — Chloro- 

 bmniomatic anhydride, byiDr. A. J. J. Vandevelde. This is 

 obtained by the action of bromine upon chlorofumaryl chloride. 

 It is easily sublimed, even at ordinary temperatures, in a current 



NO. 1343, VOL. 52] 



of dry air, and can be purified in this manner. Its formula 

 appears to be CCl.CBr.(CO).0. It fuses at 113° and boils at 

 203°. It has a very irritating but not disagreeable odour, and 

 violently attacks the nuicous membranes. It is soluble in alcohol, 

 ether, chloroform, carbon bisulphide, and benzol, and easily 

 crystallises in needles by concentration. When sublimed, it 

 crystallises in plates. Water only dissolves it slowly, and aa 

 aqueous solution, when spontaneously evaporated, gives a very 

 soluble deliquescent substance, which only crystallises when 

 nearly dry. 



Proceedings of the Si. Petersburg Society of Naturalists, vol. i. 

 No. 1-3. — The St. Petersburg Society of Naturalists has intro- 

 duced this year a most welcome improvement in its publications. 

 The Proceedings of the Society are now published separately, in 

 advance of the Memoirs, and all the communications are 

 summed up by the authors themselves in Krench or in Cerman. 

 We have already received three fascicules of the Proceedings, 

 which contain a number of interesting communications ; on the 

 petrography of central Caucasus and on \'esuvian lavas, by .M. 

 Loewinson-Lessing ; on the morphology and phylogenetic 

 relations of the .Myriapoda, by P. Schmidt, from which we learn 

 that the Paitropus Hu.xleyi is possessed of a pair of tracheas. of 

 a ver)' plain structure, which open under the mandibles ; on the 

 flora of the Zerafshan region in Turkestan, by W. Komarofi"; on 

 the embryolog)- of the Diplopodes, by N. Cholodkovsky : on the 

 l)Tnph glands of the earthworms, by G. Schneider ; on geological 

 researches in the Altai, by Prof. Inostrantsefi"; on the formation 

 of the egg in the Dytiscus, by K. Sainl-Hilaire ; and on the 

 Pantopodes of the Arctic Ocean and the White Sea, being a 

 review of the species described and collected both by the author 

 and different previous explorers, with a description of one new 

 species and two new varieties. 



Memoirs ( Trudy ) of the St. Petersburg Society of Naturalists, 

 vol. xxiv. , Section of Botany. — Beside; the Proceedings, this 

 volume contains two important works : — The sub-genus 

 Eugentiana of Tournefort's genus Gentiana, by N. Kuznetsov, 

 being an elaborate work of 530 P'lg^s, with a plate and geo- 

 graphical maps, and containing the systematic description of 

 this sub-genus, established by the author, its morphology, and 

 the geographical distribution of its species. — The flora of 

 Crimea, by W. Ageenko, part ii. , first fascicule, containing the 

 tribes from the Ranunculacese to the Capparidea;. In the first 

 volume of this work the author gave a review of the literature of 

 the subject, as well as a review of the collections of Crimean 

 plants which he had at his disposal, and an excellent sketch of 

 the flora of Crimea and its dependency from the local physical and 

 geological features of the country. Now he gives the full list of 

 the vascular plants of Crimea, which will be followed by a 

 review of the geological changes untlergone by Crimea and their 

 influence upon the present composition of the flora. 



Bollettino delta Societa Sismologica Italiana, vol. i. , 1895, 

 Nos. I, 2. — Whether, and to what extent, an earthquake-wave 

 can afibrd criteria for reasoning with regard to the nature of 

 the formations traversed by it, by Prof. P. M. Garibaldi. 

 — On conical or horizontal pendulums, by Prof. G. Grablovitz. 

 In this paper is described a simple form of horizontal pendulum 

 designed for timing, or calling attentitm to, the beginning of a 

 disturbance. The mode of susj^ension resembles that adopted 

 by ticrard and Milne, and from the mass at the free end of the 

 horizontal rod there projects downwards a wire into a small cup 

 of mercury. When the pendulum is disturbed, an electric 

 circuit is closed, and a bell is rung, or the time determined by 

 stopping a clock, cVC. - The Lecco earthquake of March S, 

 1894, by Dr. M. Baratta. This earthquake was a very slight 

 one, and its interest lies in the discovery by its means of a new 

 centre of disturbance in Lombardy, with which other slight 

 shocks may also be connected. The relation between these 

 earthquakes and the geological structure of (he district is dis- 

 cussed. — Vesuvian notes (1S92-93), by Prof. G. Mercalli. — Seis- 

 moscope for electrical registration, by Prof. G. Mugna. — 

 Geodynamic levels for continuous registration, by Prof. G. 

 Grablovitz. The author has had two water-levels constructed 

 for Ihe geodynamic observatory at Ischia. They are each 2j 

 metres long, and are arranged north-south and east-west. 

 The movements of the ground are indicated by floats, whose 

 displacements are magnified fifty times by levers carrying [wns 

 at their free ends. Copies of the record obtained from the 

 Laibach earthquake of April 14 are given. — On the velocity of 

 propagation and on the length of seismic waves, by Prof. F. 



