March 8, 1888] 



NA rURE 



455 



Paris. 



Academy of Sciences, February 27. — M. Janssen in the 

 chair. — On the doctrine of the probability of error; the law of 

 Gauss, by M. J. Bertrand. It is shown that the law of Gauss, 

 based on the postulate, "The mean of the results of any number 

 of measurements is the most probable value deducible from those 

 measurements," is incapable of rigorous demonstration. — Artifi- 

 cial produclion of rhombohedric crystals of rubies, by MM. E. 

 Fremy and A. Verneuil. Specimens were shown of these 

 crystals produced by the method described at the meeting of 

 March 14, 1887. These are very difife.ent from the rubies 

 obtained by the authors in 1877, which were produced in a 

 vitrous vein from which they were detached with great difficulty. 

 The present gems are on the contrary produced in a porous 

 and friable vein, where they occur in clusters of crystals in a 

 state of great purity, and from which they may be easily re- 

 moved. To effect this it suffices to throw the product of 

 calcination into a flask of water and shake it violently. Then 

 the vetn being light remains in suspension in the water, while 

 the heavier rubies are at once precipitated to the bottom. The 

 gems are always rhombohedric, and in every respect comparable 

 to the natural stones. They have the same colour and hardness, 

 easily scratch topaz, become black when heated, regaining their 

 beautiful pink tint when cooled, have a diamond-like brilliance, 

 and perfectly regular crystalline form. The paper was followed 

 by some remarks by M. Des Cloiseaux, to whom the specimens 

 had been submitted for a thorough crystallographic examination. 

 — On some general conditions under which nitrogen is fixed by 

 vegetable soil, by M. Berthelot. The author had already 

 established by a long series of experiments that certain argil- 

 laceous earths and certain sands have the property of fixing 

 atmospheric nitrogen and enriching themselves by a slow and 

 progressive process with organic nitrous substances obtained 

 directly or indirectly from living organisms. Since then he has 

 prosecuted the study of this interesting phenomenon, and here 

 resumes the results of his further researches. Some experiments 

 are also described on the transformation of the nitrates in the 

 soil into nitrous combinations of organic character. His ob- 

 servations tend to the general conclusion that the earth should 

 not be regarded as an inert mineral body, stable and invariable 

 in its composition until disturbed by the process of vegetation, 

 but as a body filled with living beings, and whose chemical 

 composition and abundance of nitrogen vary and oscillate with 

 the conditions determining the vitality of those beings. — On a 

 method of quantitative analysis of chloroform, and on the 

 solubility of this body in water, by MM. G. Chancel and F. 

 Parmentier. Priority of discovery is claimed by the authors for 

 this process, which, in a recent communication to the Academy, 

 M. L. de Saint-Martin describes as new. — The Neolithic epoch 

 at Champigny, by M. Emile Riviere. The results are described 

 of the researches that have been carried on since 1867, by MM. 

 Le Roy des Closages, Carbonnier, and the author, at the 

 Neolithic station near the village of Champigny in the Depart- 

 ment of the Seine. Here have been found numerous flint 

 implements, scrapers, arrow-heads, polished hatchets, knives, 

 besides four grind- stones and much coarse pottery curiously 

 ornamented, all in association with the bones of the horse, pig, 

 deer, roebuck, and ox. The material of some of the implements 

 points at long migrations, or else a widespread intercourse with 

 more or less remote tribes, the rocks used in their fabrication 

 occurring in the region stretching from Belgium to Chiavenna in 

 the Italian Alps. — Elements and ephemeris of the planet 272, by 

 M. Charlois. These elements are the result of three observations 

 made at the Observatory of Nice on Febmary 4, II, and 18, — 

 Permanent deformation and thermodynamics (continued), by M. 

 Marcel Brillouin. The chief feature of the present study is the 

 determination of the consequences of the axiom of Clausius. — 

 Experimental researches on the variations produced by a shock 

 in the magnetic condition of a steel bar, by M. G. Berson. It 

 is shown generally that the shoc'xs or impacts given to steel bars 

 have the effect of facilitating the disposition of the molecules in 

 a given direction under the action of the stimulating forces, by 

 diminishing for a very brief interval the molecular friction known 

 as coercing force. — On the laws of chemical equilibrium, by M. 

 H. Le Chatelier. This is a reply to a recent communication 

 from M. Duhem claiming priority in connection with a law of 

 thermo-chemistry lately enounced by the author. — Action of 

 aniline on epichlorhydrine, by M. Ad. Fauconnier. Continuing 

 the researches of M. Hermann, the author has succeeded in ob- 

 taining one of that chemist's anticipated bases, which results 



constant relation — - under 



from the combination of two molecules of aniline with one of 

 epichlorhydrine. The mode of preparation and properties of 

 this body are described.— On the respiration of com yeast at 

 various temperatures, by MM. Grehant and Quinquaud. Con- 

 tinuing the classical studies of MM. Pxisteurand Schiitzenberger, 

 the authors have carried out a series of experiments to- 

 measure the volume of oxygen f.bsorbed and of carbonic acid 

 produced by yeast living at first in distilled water in the absence 

 of sugar and in contact with a determined volume of air. They 



CO 

 hnd that the relation - — -^ is variable with the temperatnrcr 



so that the isolated yeast-cells would appear to behave differently 

 from the fungi and tissues lacking chlorophyll, which give a 



all temperatures for the same 



individuals of the same species. 



Astronomical Society, February i, — M. Flammarion, 

 President, in the chair. — M. Flammarion expressed his admira- 

 tion of what he had seen at the Nice Observatory on a recent 

 visit. In the great equatorial (30 inches aperture), the Orion 

 nebula is splendid, stars of the sixteenth magnitude seem bright, 

 and double stars from o""l to o" 3 apart are discovered. — M, Flam- 

 marion observed the lunar eclipse on January 28 at Nice. The 

 moon remained easily visible during totality, and of a bright 

 copper hue. The Nice Observatory is 375 metres above the 

 level of the Mediterranean Sea. In the finder of the great 

 equatorial the shadow was fringed with a transparent border 

 about 2' in breadth. MM. Henry Brothers and M. Trouvelot 

 remarked the contrast this eclipse presented with that of October 

 1884, in which the moon nearly disappeared. M. Detaille said 

 that he had been struck by the very fine colour of the moon ; the 

 earth's shadow, though ill-defined on the edge, was quite circu- 

 lar. — MM, Henry showed a photograph of the Pleiades takea 

 with their 34-centimetre object-glass, and an exposure of four 

 hours. The negative included stars down to the seventeenth mag- 

 nitude. Much new nebulous matter is discovered in this photo- 

 graph. One of the bright stars is enveloped in a dense nebula 

 hitherto unseen. Several singular long thin streaks of nebulous 

 matter extend in some cases from star to star to a considerable 

 length. — M. Berteaux, geographical editor, presented the Society 

 with a new map of the moon by M. C. Gaudibert, the well- 

 known selenographer. This map has been made from M. 

 Gaudibert's observations and revisals ; it has been drawn by M. 

 Tenet, and reproduced by heliography. The diameter of the 

 disk is 64 centimetres. 



Berlin. 



Physical Society, February 3. — Prof, von Helmholtz, 

 President, in the chair. — Prof. Paul du Bois Reymond spoke 

 on the difficulty of forming any conception of force acting across 

 an intervening space. From among the various instances of such- 

 forces the speaker selected gravity for a thorough discussion. He 

 explained the six properties characteristic of this force, pointing 

 out that only two of them — viz. the proportionality to the mass, 

 and the law of inverse squares of the distances — can be proved 

 experimentally, while someof its other properties, as, for instance, 

 the independence of gravity from the condition of motion of the 

 mass, are much doubted by many observers. Prof, du Bois 

 Reymond then discussed the ever-recurring endeavours in past 

 times to arrive at some mechanical construction for gravity, en- 

 deavours which were in all cases unsatisfactory, since they were 

 always dependent either on the fundamental properties of matter, 

 which are themselves incomprehensible, or upon physical phe- 

 nomena whose basis was still undetermined. Just as in the case 

 of many problems the experiments for whose solution have been 

 repeated until their inaccuracy was clearly proved, so also in 

 the case of gravity has a mechanical conception been repeatedly 

 sought for : hence it becomes necessary to show that gravity \s 

 beyond our comprehension, and the speaker proceeded to do 

 this by showing that Lesage's theory of the impact action of the 

 atoms of ether, which has been so long and persistently believed, 

 while it explains the law of inverse squares does not explain the 

 proportionality to the mass, and in certain special cases leads to per- 

 fectly impossible results. Gravity is therefore incompiehensible, 

 and Newton's view that it is something inherently present in all 

 matter is correct, since it is by means of this force alone that 

 matter is made evident to us ; indeed, as far as the matter itself 

 is concerned, it may be entirely left out of account. — Prof. 

 Ilelmholtz then explained how he is in the habit of treating the 

 subject of gravity in his lectures. He represents it as being that 



