July i 9) 1883] 



NA TURE 



287 



lower infantile mortality. The Jews present a much more rapid 

 increase of numbers than either of the other two religious bodies, 

 for, although their natality is less than either, their mortality is 

 remarkably low for all age-, these conditions being probably due 

 to their dietetic and hygienic regulations, the infrequent occu- 

 pation of women out of their homes, early marriages, and general 

 sobriety. 



SOCIETIES AND ACADEMIES 



Er'INUTRGH 



Royal Society, July 2. — The Astronomer-Royal for Scot- 

 land communicated a paper, which was read by Prof. Crum 

 Brown, on the group b in the solar spectrum, as observed with 

 the remarkably line spectroscope which Prof. Tait had recently 

 secured for the University. The main conclusion come to was 

 that the speculations regarding the existence of basic lines were 

 unwarrantable, since the lines b 3 and b 1 were both distinctly 

 double lines, each real single line in all probability being due to 

 one of the substances, magnesium, iron, or nickel. The paper 

 gave a complete historical statement of the observations of the b 

 group by Swan, Angstrom, Thalen, Young, and others, since 

 the year 1830. — Prof. C. G. Knott read a paper on superposed 

 magnetisms in iron and nickel. The experiments were, in part, 

 a repetition of Wiedemann's well-known investigations into the 

 twisting of iron wire under the influence of longitudinal and 

 circular magnetisations. With a steady current along the wire, 

 and a varying current in a helix round the wire, a twist was 

 obtained which in almost every case reached a maximum for an 

 intermediate value of the helical current. The maximum oc- 

 curred sooner when the longitudinal current was diminished. 

 No such maximum was obtained in the case of nickel, which 

 twisted more and more for greater and greater currents, until the 

 point of magnetic saturation was reached. Again the nickel 

 twisted in the opposite direction to iron, other things being the 

 same — a result in accordance with Parrett's observation that 

 nickel contracts when magnetised, while, as Joule first proved, 

 iron extends. The effect of weighting the wires so as to subject 

 them to different tensions, was also investigated, the general 

 result being that the twist was greater for the smaller weight, 

 except for special combinations of current strengths and weights. 

 — Prof. Tait gave further results as to the lowering of the 

 maximum density point of water under increased pressure. By 

 an improved method he estimated the lowering to be 2°"] C. for 

 one ton's weight per square inch, a result in wonderful agreement 

 with that obtained by the indirect method carried out by Pro- 

 fessors Marshall and Smith and Mr. Omond. — In a note on 

 surface emissivities, Prof. Tait drew attention to the apparent 

 lack of data on this subject, which, however, could be largely 

 supplied from the numerous observations by Prof. Forbes and 

 himself on the rate of cooling of the bars used in the conduction 

 of heat experiments. — Prof. Tait also submitted to the Society a 

 photograph of the markings on the arm of the boy who had 

 been struck by lightning at Duns some weeks ago. 



Paris 

 Academy of Sciences, July 9. — M. Blanchard, president, 

 in the chair. — On the pyroelectricity in blende, chlorate of 

 sodium, and borazite, by MM. C. Friedel and J. Curie. — On 

 the separation of gallium from tellurium and silicium, by M. 

 Lecoq de Boisbaudran. — Observations on M. Hirn's recently 

 published work on " The Phenomena due to the Action of the 

 Atmosphere on Falling Stars, Aerolites, and other Meteoric 

 Objects," by M. Daubree. In this work the author argues that 

 the apparition of all kinds of meteors in space, their luminosity 

 aud explosion, and accompanying sounds depend directly and 

 exclusively on their velocity. This general conclusion is ques- 

 tioned by M. Daubree, who points out that account must also be 

 taken of the chemical action produced at contact of meteoric 

 substances with the atmosphere. — On the infra-red spectra 

 emitted by metallic vapours, by M. Henry Becquerel. The 

 metallic vapours here dealt with are those of sodium, mignesium, 

 calcium, potassium, silver, and thallium. The method of 

 analysis described by the author opens a new and wide 

 field of observation, comprising between the wave-lengths 760 

 and 1300 an interval of wave-lengths greater than that existing 

 between the extreme red of the visible spectrum and the last- 

 known ultra-violet rays. — Researches on the destruction and 

 jtilisation of the bodies of animals that have died of contagious 



diseases, and especially carbon poison, by M. Aime Girard. 

 The method here proposed consists in dissolving the carcasses at 

 a low temperature in concentrated sulphuric acid, and then 

 utilising the liquid thus obtained in the production of a 

 superphosphate of azotic lime. — A protest is presented to 

 the Academy on MM. Delattre's recent paper (meeting of 

 May 21) on the treatment of the waters used in wooln ashing. 

 MM. Gaillet and Huet claim to be the real authors of the pro- 

 cess, and support their claim by sundry documents. — On 

 the conditions of the subsoil under the Berlin Observatory ; 

 letter addressed to M. Faye by M. Foerster. — On a method 

 capable of furnishing an approximate value for the integral 



/+ «: 

 _ x F(x) dz, by M. G. Courier. — Generalisation of the theo- 

 rem of Jacobi on the partial determinants of the adjunct system, 

 by M. Em. Barbier. — On the reduction of equations, by M. A. E. 

 Pellet. — On a lever, a new system of Roman balance with auto- 

 matic slider, by M. A. Picart. — General formulas of centred 

 dioptric systems, by M. Monoyer. — A new method of determin- 

 ing the limits of electrolysis, by M. Ch. Truchot. — On samarium, 

 by M. P. T. Cleve. — On the blue colour obtained by the action 

 of chromic acid on oxygenated water, by M. II. Moissan. — On 

 tetric acid and its homologues, by M. W. Pawlow. — On the 

 dimorphism of iodide of silver, by MM. Mallard and Le Chate- 

 lier. — On some new characteristic reactions of salts of gold, by 

 M. Ad. Carnot. — On the alcoholates of soda, by M. de For- 

 crand. — On the pyrogenation of colophany, by M. Ad. Renard. 

 — Researches on the curve of muscular shocks in various mala- 

 dies of the nervo-muscular system, by M. Maurice Mendelssohn. 

 — Development and structure of tuberculous begonias, by M. 

 Henri Duchartre. — Contributions to the study of the fermenta- 

 tion of breadstuffs, by M. L. Boutroux.— The microbes of the 

 lymph of marine fishes, by MM. L. Olivier and Ch. Richet. 

 The presence of parasites is clearly determined, and the authors 

 conclude that microbes are nearly always present in the lymph, 

 and consequently in the very tissues of the marine fishes. — 

 Method of determining the quality of the wines of the south of 

 France, by M. A. Audoynaud. 



Berlin 



Physical Society, June 8.— Dr. Martius discussed the two 

 recently-discovered instruments which are employed for the 

 measurement of small frequently-occurring variati' ins of a current, 

 the telephone and the capillary electrometer. The latter, as is 

 well known, was constructed about ten years ago by Mr. 

 Lippmann in the laboratory of Herrn Kirchhoff, and is based 

 on the principle that a current passing through a meniscus 

 changes its surface tension, and causes a mov.ment of the 

 meniscus. The frequent variations of weak cur ents are indi- 

 cated with difficulty, if at all, by galvanometers and tangent 

 compasses, but the capillary electrometer can make such varia- 

 tions, especially as they occur inelectrophysioloty, visible to the 

 eye. It has therefore quite latterly been einpi yed in physio- 

 logical experiments, and Dr. Martius has undertaken to investi- 

 gate the capabilities of the apparatus in the form designed by 

 Prof. Christiani, and described below. A ghs tube drawn out 

 at one end to a capillary, and partly filled with mercury, stands 

 vertically in a large glass vessel also containing some mercury, 

 and above it dilute sulphuric acid, in which the capillary point 

 of the tube dips, so that the acid passes into the tube and up to 

 the mercury meniscus. The position of the latter is read with a 

 microscope. Metal wires are dipped into the mas of mercury, 

 and a current can then be sent through the ca|.i lary t .lie, the 

 current causing a motion of the mercury meniscus citlv-r upvi ards 

 or downwards according to its direction, on a p -iiive current 

 flowing downward from the mercury in the tube mi 'vmg the menis- 

 cus downwards, a negative current, upwards. In ihts apparatus 

 care must be taken to keep the current too weak 10 cau-e elec- 

 trolysis of ihe acid; otherwi-e the instrument becomes useless 

 and must be refilled. The observations were first made with a 

 constant current which was interrupted at will, and they showed 

 that under exactly similar conditions the displacement which a 

 positive current produced were always greater ihan tho-e caused 

 by a negative current of like strength. On making and breaking 

 contact rapidly, for instance about twelve times a second, a 'otal 

 displacement of the mercury, corresponding to the direction of 

 the current, was observed, and also oscillations of the meniscus, 

 the number of which was equd to the numb r of interruptions 

 of the current. If the number of interruptions wis increased, a 

 stronger current had always to be used in order to make the 



