304 



NA TURE 



\jfa7i. 24, I i 



Italian corvette Caracioh, who informed him that it wai used 

 by the natives of the Chiloe Islands as a kind of barometer to 

 foretell the approach of either dry or wet weather. This 

 " Barometro Araucano, " which consisted merely of the shell of 

 a crab, pronounced by Mr. Haswell to be one of the Anomiira, 

 probably of the genus IJthodes, is most peculiarly sensitive to 

 atmospheric changes. In dry weather it remains nearly white, 

 but, with the approach of moisture, small red spots appear on 

 the shell, increasing in number and size with the increase of 

 humidity, until during the wet season it becomes completely red, 



Paris 

 Academy of Sciences, January 14. — M. RoIIand in the 

 chair. — On the researches of M. Guntz in the thermo-chemistry 

 of the fluorides, in reply to the strictures of M. Tommasi, by M. 

 Berthelot. — On a process of anaesthesis by the method of titrate 

 mixtures of vapours and air ; its application to the human sub- 

 ject in the form of vapours of chloroform, by M. Paul Bert. The 

 chief advantages of this process are stated to be : delirium 

 always slight, somefimes altogether absent, even in adults ; abso- 

 lute and regular insensibiPty obtained in six to eight mimites ; 

 quiet sleep ; normal breathing, circulation, and temperature ; no 

 symptoms of nausea ; normal and perfectly reassuring appear- 

 ance of the patient while asleep ; constant and always very pro- 

 tracted consecutive ana^sthesis ; great economy in the outlay for 

 chloroform. — Generalisation and strictly mechanical demonstra- 

 tion of Joule's electrical formula, w = iey, by M. A. Ledieu. 

 — On the preparation in large quantities of artificial virus 

 attenuated by rapid heating, by M. A. Chauveau, By this pro- 

 cess sufficient virus for the prophylac'ic inoculation of from 

 4000 to 8000 sheep may be rapidly prepared in the same reser- 

 voir. — Observations of the Pons- Brooks comet made at the 

 bent equatorial of the Paris Observatory, by M. Perigaud. — On 

 the genus of some entire functions in mathematical analysis, by 

 M. Laguerre. — On the geometrical curve known as Pascal's 

 "lima9on,"by M. A. Genocchi. — On linear differential equa- 

 tions with doubly periodical coefficients, by M. G. Floquet. — 

 On the adiabatic expansion of the vapour of water, by M. P. 

 Charpentier. — On the agreement of experience wilh the general 

 theoretic law regulating capillary surfaces, especially in its 

 application to water confined between two moistened plaques, 

 vertical and parallel, by M. Quet. — On a new method of deter- 

 mining the magnetic inclination by means of the induc- 

 tion compass, by M. Wild. — On the observation of earth 

 currents who~e intensity is shown to be subject to secondary 

 fluctuations depending on the degree of moisture and tempera- 

 ture of the zone comprised within the circuit, by M. Larroque. — 

 Determination of the intensity of combustion in some acetones 

 and in the two ethers of carbonic acid, by M. W. I.ouguinine. — 

 On the phenomena of chemical dissociation, by M. Isamhert. 

 Here the author endeavours to resume the results of his experi- 

 mental researches on dissociation in a simple theory based on 

 the thermic data, by means of which alone it is possible to 

 appreciate chemical phenomena. — On the preparation of the 

 sulphate of the sesquioxide of pure chromium, by M. H. Bau- 

 bigny. — Explanation of a method for determining the density of 

 liquid oxygen, by M. Menges. The author obtains the equation 



V d 

 d = — ! — L, where d = the density of the liquid gas, z' = its 



W - Wj 



volume, V = the volume of the gaseous portion, all known 

 quantities. — On colloidal ferric ethylate and ferric hydrate, by M. 

 Ed. Grimaux. — On a chloruretted silicate of manganese, by M. Al. 

 Gorgeu. — On the influence of plastering on the composition and 

 the chemical properties of wine, by M. L. Magnier de la Source. 

 The plastering process with chemically pure sulphate of lime has 

 the effect of decomposing not only the cream of tartar, but also 

 the neutral organic combinations of potassium which are present 

 in a very considerable proportion in the perfectly ripe grape. — 

 On the presence of the diamond in some graphic stone occurring 

 near Kellary, Madras Presidency, by M. Chaper. — On the fossil 

 Echinida; of the Eocene formations at Saint-Palais (Charente 

 Inferieure), by M. G. Cotteau. 



Berlin 

 Physical Society, Januaiy 4. — Prof. Neesen briefly commu- 

 nicated the contents of a paper sent in by Herr Friedrich C. S. 

 Midler, describing three apparatus used in connection with the 

 delivery of lectures : a tangent compass, a galvanometer, and 

 a rheostat. These in^trumenls were intended to take rapid 

 measurements, and to render them visible to a large audience. 



Following up this subject. Prof. Neesen gave a short account of 

 the contrivance by which in his lectures he measured the mutual 

 attraction of two magnets by means of scales. In conclusion, 

 he reported experiments instituted by him with a view to deter- 

 mining the influence of magnetisation on electrical conducting 

 power. In these experiments he had made use of a magnetic 

 substance of high specific resist.ance, a solution of chloride of 

 iron. Two equal tubes were filled with the same solution, and 

 inserted as the two branches of a Wheatstone bridge into the 

 circuit of a galvanic battery ; the two other branches being so 

 arranged that the galvanometer stood at zero. The electrodes 

 in the tw o tubes consisted of iron plates, and were exactly alike. 

 The tubes, that is, the fluid conductors, had in the different experi- 

 ments different shapes and different diameters. The contents of 

 the one tube were then magnetised either by a magnetising spiral 

 or by a powerful electromagnet, and the galvanometer was 

 observed during this process of magnetisation. The result of 

 the experiments was in every case a negative one. Very slight 

 deflexions were indeed observed in the galvanometer needle in the 

 case of the experiments with the magnetisiu'j spiral, but these 

 proceeded from the slight heating of the fluid, an effect 

 which, notwithstanding the solution of chloride of iron was sur- 

 rounded by a casing of circulating water, had not been wholly 

 avoided. In those experiments, on the other hand, in which the 

 magnetisation was made by means of the electromagnet, the 

 needle remained invariably at rest. — Prof. Rceber di-cussed and 

 explained the principle of experiments made on the Rhone and 

 reported in the Comptes Rendus. These experiments had for 

 their object the towing of ships by means of ropes wound round 

 the whole vessel. — Dr. Koenig gave a short preliminary com- 

 munication on the experiments, which, in cooperation with Dr. 

 Dietrici, he had made, with a view to determining the precise 

 position of different spectral colours and the sensitiveness of the 

 eye for distinguishing colours. At the next meeting of the 

 Society he would speak at greater length on the subject, illus- 

 trating it by numerical data. 



CONTENTS Page 



The Alps of New Zealand. By Prof. T. G. Bonney, 



F.R S 2S1 



Dobson's " Monograph "of the Insectivora." By 



Prof. W. H. Flower, F.R.S 2S2 



Our Book Shelf:— 



Galbraith and Haughton's "Manual of Mathematical 



Tables" 2S2 



Remsen's " Principles of Theoretical Chemistry " 283 



" Studies in Micrographic Petrography " 2S3 



Letters to the Editor :— 



The Remarkable Sunsets. — Prof. Edward Divers ; 

 H. M. Paul ; Rev. John Hawaii ; T. Story- 

 Maskelyne ; J. Edmund Clark ; Hon. F. A. 



R. Russell 283 



Unconscious Bias in Walking. — G. H. Darwin ; 



Thos. Hawksley 286 



Diffusion of Scientific Memoirs.— R. T. Glazebrook 287 

 Recent Low Temperatures in America. — Dr. John 



Rae, F.R.S 287 



Meteors— Unpublished Notes of November 30, iS:c. — 



Donald Cameron 2S7 



British Aphides 288 



Earthquakes and Buildings. By Prof. John Milne . 290 

 The Late Eruption of Vesuvius. By Dr. H. J. 



Johnston-Lavis 291 



The Egyptian Sudan and its Inhabitants. By Prof 



A. H. Keane (With Map) 291 



Notes 294 



Our Astronomical Column : — 



A .Southern Comet 296 



Pons' Comet 296 



Professor Haeckel on the Orders of the Radiolaria. 



II 296 



University and Educational Intelligence 299 



Scientific Serials 300 



Societies and Academies 300 



