ment of I mm. The column oscillates with each change of temperature and each variation of gravitation, but is not affected by changes of pressure, since the tube is kept closed at the top. Under these circumstances, the instrument in question is capable of indicating the change of gravitational force due to the change in the position of the moon by a displacement of 0:46 mm. The apparatus is difficult to set up, and will require some improvement before it can give trustworthy results. -Observation on the conditions which appear to have obtained during the formation of meteorites, by M. Daubrée. The heterogeneous structure of meteorites, the innumerable iron granules disseminated through the stony matrix, so different from the well-defined and voluminous crystals obtained by the fusion of the constituent minerals in the laboratory, and M. Stanislas Meunier's success in imitating meteorites by means of gaseous reactions, lead to the conclusion that they have not been produced by fusion, but by a sudden precipitation of different gases into the solid state. -On the preparation of uranium at a high temperature. Rapid preparation of chromium and manganese at a high temperature, by M. Henri Moissan (see Notes). -On stereochemistry, by M. C. Friedel.-On the benzoates and metanitro-benzoates of diazoamidobenzene and paradiazoamidotoluene, by MM. A. Haller and A. Guyot.-High atmospheric pressures observed at Irkutsk from January 12 to 16, 1893, by M. Alexis de Tillo. During four days the barometer remained above 800 mm., and on January 14 the highest value known up to the present, 8075 mm., was reached, the temperature being - 46°3 C.-M. Callandreau was elected Member in the place of the late Admiral Mouchez; and M. Kékulé Correspondent in the place of the late M. Stas.-Summary of solar observations made at the royal observatory of the Roman College during the last quarter of 1892, by M. P. Tacchini.On the terms of the second order resulting from the combination of aberration and refraction, by M. Folie.-On the essential singularities of differential equations of a higher order, by M. Paul Painlevé,-Remarks on the preceding communication, by M. É. Picard.-On uniform integrals of linear equations, by M. Helge von Koch.-Generalisation of Lagrange's series, by M. E. Amigues.-On the part played by the steam jacket in multiple expansion engines, by M. A. Witz.-A direct-reading stereo-collimator, by M. de Place.-Hysteresis and dielectric viscosity of mica for rapid oscillations, by M. P. Janet. A comparison of differences of potential and resulting charges during rapid oscillations, determined by means of the apparatus described last year, reveals a lagging of the charge behind the potential, both increasing and decreasing, and a curve plotted with the values obtained for a mica condenser suggests some analogy with Ewing's curves of magnetic hysteresis.-Optical field, absolute, and relative field of view of the human eye, by M. C. J. A. Leroy. On the achromatism of semioircular interference fringes, by M. G. Meslin.-A new system of atomic weights, partly founded upon the direct determination of molecular weights, by M. A. Leduc. -Decomposition of the alkaline aluminates by carbonic acid, by M. A. Ditte.On mixtures of ether and water, by M. L. Marchis.-On the heat of formation of arragonite, by M. H. Le Chatelier.On the crystalline forms of chromium and iridium, by M. W. Prinz.-Ammoniacal fermentation of earth, by MM. A. Muntz and H. Condon. -On the composition of the salts employed as condiment by the people about the Oubangui, by MM. J. Dybowski and Demoussy.-Oxyhæmatine, reduced hæmatine, and hæmochromogen, by MM. H. Bertin-Sans and J. Moitessier. On the histological alterations of the cerebral cortex in certain mental diseases, by M. R. Colella.-On the structure and growth of the calcareous shell of the barnacle (B. tintinnabulum), by M. Gruvel.-On the causes of the green colour of oysters, by M. S. Jourdain.-Geological remarks on the diamond-bearing meteoric irons, by M. Stanislas Meunier.

AMSTERDAM.

Royal Academy of Sciences, January 28.-Prof. van de Sande Bakhuysen in the chair.-Mr. Kapteyn dealt with the distribution of stars in space, It has been long known that the mean proper motion in the galaxy is smaller than elsewhere. A thorough investigation of the proper motion of all the stars of the Draper catalogue observed by Bradley in both co-ordinates (2357 stars) shows, that this fact is due to an excess of insensible or very small proper motion in the milky way. Those exceeding

o"055 show no aggregation towards that zone. As far as theen dence goes, it further proves, by means of the angle subtene by the solar motion in space, that stars with equal proper mo in and out of the galaxy have nearly equal distances. These w facts taken together prove that Struve's theory of the arra ment of the stars in space must be abandoned. In order to t what arrangement must be substituted Mr. Kapteyn has co sidered the stars of the first and second spectral type separate and arrives at the conclusion that the latter are very strong condensed about a centre not far from our system, approxima in the direction of oh. R. A. and +42° of decl., whilst the sa of the first type are more nearly evenly distribute in the prxmity of our sun. Notwithstanding this difference in arrange ment Mr. Kapteyn thinks that probability points to the cr clusion that the two types belong to one and the same system (1) Because the centre of condensation of the second type str coincides very nearly with the apparent centre of the milky (which seems to consist mainly of first type stars). (2) Bene the stars with insensible proper motion of both types are strutt condensed towards the plane of the milky way. (3) Because gr of stars, which undoubtedly form stellar systems (eg. Hi contain stars of both types.-Mr. van Bemmelen, in persu inquiry on colloidal hydrates, spoke at the meetings of Nove 26, 1892, and of January 28, 1893, on the constitution composition of the hydrogels of SO, and of CuO, as they result from his determinations of their tension of (at 15°), changing in a continuous way with their tenure of wate -Mr. Kamerlingh Onnes showed the isodynamics of physical laboratory at Groningen, mapped under Prof. Hap direction with the localvariometer by Mr. Wind, proving excellent constancy of the magnetic field. A new theory localvariometer points to another ratio of distances of the flecting magnet-pairs than that given by Kohlrausch as prefe -Mr. Schoute treated of "the uniform representation of 1 surface on a plane." Indication of the number of points mon to two curves on F3, the plane representations of whic given. Application as to the position of the twenty-sevea with respect to one another.

CONTENTS.

Modern Optics and the Microscope. By Rev. Dr.
Dallinger, F.R. S..

A University Extension Manual
Our Book Shelf:-

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C.M.G., F.R.S..

The Flight of Birds.-Herbert Withington
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British New Guinea.-Prof. Alfred C. Haddon
Henry O. Forbes

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Comet Brooks (November 19, 1892).
Comet Holmes (1892 III.)

Nova Auriga

Hydrogen Line HB in the Spectrum of Nova Arg Coincidence of Solar and Terrestrial Phenomena Astronomical Journal Prizes.

Geographical Notes

Mongolia and Central Tibet

Gases in Living Plants.

By J. C. Arthur

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