November 28, 1907] 



NATURE 



95 



real roots is determined without any ambiguity by the 

 situation of (X, V), whether it is in one of these regions 

 or on a bounding line. — The application of quaternions to 

 the problem of the infinitesimal deformation of a surface : 

 J. E. Campbell. Weingarten's characteristic function in 

 this problem can be interpreted kinematically as the normal 

 component of the rotation, which an element of surface 

 undergoes in the course of the deformation. The direct 

 application of the method of moving axes, to obtain the 

 characteristic equation, can be simplified very much by the 

 use of quaternions. — -Addendum to a paper on the inversion 

 of a repeated infinite integral: T. J. I'A. Bromwich. — 

 Generalisation of a theorem in the theory of divergent 

 series : G. H. Hardy. — Uniform and non-uniform con- 

 vergence and divergence of a series, and the distinction 

 between right and left : Dr. \V. H. Young. — Nodal cubics 

 through eight given points : J. E. Wright. — .\ transform- 

 ation of hypergeometric series : Dr. E. W. Barnes. — .\ 

 transformation' of a certain hypergeometric series : Prof. 

 M. J. M. Hill. — S. general theorem on integral functions 

 of order less fhan one-half ; J. E. Littlewiood. 



P.vuis. 

 Academy of Sciences, November II. — M. A. Chauveau 

 in the chair. — .\ new mineral species, arising from the 

 Athenian plumbiferous scoria of Laurium : .-\. Lacroix 

 and .\. de Schulten. This is one of a se.ies of minerals 

 arising from the action of sea water upon scoria rich in 

 metallic lead and galena. Its composition corresponds to 

 the forinula Pbj(AsO,),,3PbCl,. The crystallographic 

 measiirements are given, and the hardness (3-5) and density 

 (7-1) nieasur.ed. The name georgiadesite is proposed for 

 the mineral. — The influence of feeding on the course of 

 experimental tuberculosis : MM. Lannelongue, Achardi 

 and Gaillard. In sixty strictly comparative experiments, 

 in three classes of diet in which fat, carbohydrate, and 

 nitrogenous food respectively predominated, the animals 

 with the fatty food died in forty days ; with sugar, eighty- 

 seven days; and with gluten, 371 days. This confirms the 

 result of the authors' early work, clearly demonstrating 

 the superiority of a strongly nitrogenous diet in fighting 

 tuberculosis. — Continued algebraic fractions : Edmond 

 Maillet. — The periodic solutions of the equation 



AH-t-Aa(.v, y, 3)« = o : 

 .\. Myller. — The method of colour photography of MM. 

 .\. and L. Lumifere : Adrien Guebhard. A discussion of 

 the phenomena attending the reversal of the image in 

 this process. — The measurement of the anomalous dis- 

 persion in crystals at different temperatures, and on some 

 theoretical consequences : Jean Becquerel. It is shown 

 that the large increase of intensity observed for the 

 majority of the absorption bands of tysonite when the 

 crystal is plunged into liquid air is not entirely due to the 

 contraction of the bands, but is also caused by an increase 

 in the total energy absorbed, corresponding to the increase 

 in the dielectric coefficient of the electrons. — .A comparison 

 of the effects of the X-rays and radium upon the plant 

 cell. \'alue of the unit M in plant physiology : H. 

 Guillemlnot. — The action of radium bromide on precious 

 stone of the alumina family : F. Bordas. ,\ modification 

 of the method described in a previous paper. Colourless 

 corundum has been transformed into topaz, the depth of 

 colour of natural topazes increased, and a similar effect 

 produced with faintly coloured rubies. Colourless fused 

 alumina, submitted to the action of radium bromide, be- 

 came first rose-coloured and then reddish yellow. Since 

 this action takes place equally well at —200°, the con- 

 clusion is drawn that the phenomenon of coloration is not 

 due to oxidation. — The diastatic function of colloids : J. 

 Ouclaux. From a quantitative study of the catalysis of 

 hydrogen peroxide solutions by colloidal solutions of ferric 

 hydrate, the author concludes that the hydrolysed part of 

 the salt does not intervene in the catalysis, and that it is the 

 undecomposed ferric chloride which effects the change. — 

 The action of gold on the dioxide of sodium and barium : 

 Fernand Meyer. Precipitated gold reacts with fused 

 sodium dioxide, yielding sodium aurate, and barium dioxide 

 attacks gold similarly, although the reaction is less com- 

 plete. From these substances auric acid can be prepared 

 by the action of sulphuric acid, .\uric acid, dried in a 

 vacuum in the dark, has the composition .\u,03,3H,0 or 



NO 1987, VOL. ']-]~\ 



.\u(OH)3. The preparation of the pure aurates of sodium, 

 potassium, barium, strontium, and calcium from this acid 

 is described. These aurates are decomposed by heat or 

 light, the insoluble residue being .-\UjO, and not gold as 

 supposed by Fremy. — The preparation of some iodides 

 in vacuo : Marcel Guichard. The preparation of the 

 anhydrous iodides of iron, nickel, silicon, and aluminium 

 is described. — The action of amorphous arsenic on the alkyl 

 halides : X. Auger. .Amorphous arsenic, prepared by the 

 reduction of a hydrochloric acid solution of arsenious 

 anhydride with stannous chloride or a hypophosphite, is 

 very active. It reacts with methyl iodide at the ordinary 

 temperature, and at higher teinperatures in sealed tubes 

 with CCI,. CHCl,, C,,H,Br,, C„H,I,, CHI,, and various 

 alkyl iodides. — The iodohydrins and alkyliodohydrins 

 derived from styrolene : Marc Tiffeneau. — The action of 

 urea, thiourea, urethane, and some amides on xanthydrol ; 

 R. Fosse. — The application of the Hoffmann reaction to 

 sparteine : Charles Moureu and .\mand Valeur. — The 

 estimation of fat in skimmed milk : R. Leze. Three litres 

 of the milk are mixed with ammonia and caustic soda, and 

 the w^hole passed through a centrifugal separator. — The 

 coloration of certain precious stones under radio-active 

 influences : Daniel Berthelot. — The products of the 

 volcano Monte Ferru, Sardinia : M. Deprat. — The in- 

 fluence of high altitude on the loss of water by the 

 organism : H. Guillemard and .\ug. Moog. The effect 

 of high altitude is not to increase the rate of loss of 

 moisture from the body, but, on the contrary, to reduce it. 

 The e.xperiments leading to this conclusion were conducted 

 at Paris, Chamonix (lojo metres), Grands-Mulcts (3o';o 

 metres), and the summit of Mt. Blanc (4810 metres). — The 

 development of the energy of the voice : M. Marage. .A 

 description, with diagrams, of a set of exercises to increase 

 the volume of air expelled from the lungs. — The visibility 

 of night signals at sea : Andr^ Broca and M. Polack. 

 The practical conclusions drawn from this investigation 

 are as follows. If a signal of doubtful colour is better 

 seen by direct vision than by indirect vision, it is red. 

 In the contrary case the light is blue or colourless. ^.A 

 new method of determining the accelerating power of 

 neutral potassium and sodium salts on the coagulation of 

 milk by vegetable ferinents : C. Gerber. — The mitosis of 

 cells containing Bacillus cueiwti : L. Mercier. — The ex- 

 perimental study of medicines stimulating the moveinent 

 of the stomach by the aid of fluoroscopy : G. Carrifere. — 

 A new Myxomycetum, an endoparasite of insects : Louis 

 Leger. 



November iS. — M. Henri Becquerel in the chair. — The 

 transit of Mercurv across the sun of November 13 and rj, 

 1007. Observations made at the Observatory of Nice : M. 

 Bassot. — Observations of the Daniel comet, 1907^, and 

 a general plan of organisation for the complete physical 

 studv of comets : H. Deslandres. — The transit of Mercury 

 of November 14, 1907, at the Observatory of Lyons : Ch. 

 Andre. — Observations made at the Observatory of 

 Toulouse of the transit of Mercury of November 13-14 : 

 B. Baillaud. — Similar observations made at the Observ- 

 atory of Marseilles : E. Stephan. — Similar observations 

 from the Observatorv of Bordeaux : L. !?icart and E. 

 Esciangon. — Similar observations from the Observatory 

 of Bourges : Th. Moreux.' — The occultation of the satellites 

 of Jupiter : G. Le Cadet. — The observation of the transit 

 of Mercury across the sun, November 13-14, 1907; 

 -A. de la Baume Pluvinel. — Remarks on the relation 

 between the solar activity and magnetic perturbations ; 

 MM. CIrera and Baicelli. — The transit of Mercury, 

 November 13-14, at the Observatory of Besanfon : MM. 

 Bruck, Chofardet, and J'ernet. — The correction of the 

 astigmatism of doubly refracting prisms : C. Tissot and 

 F^lix Pellin. The astigmatism can be corrected by the 

 use of an appropriate cylindrical lens. — The propagation 

 of telephone currents on subterranean lines : Henri 

 Abraham and M. Devaux-Charbonnel. — The magnetic 

 double refraction of organic liquids : A. Cotton, H. 

 Mouton, and P. Weiss. — The multiplicity of sounds 

 emitted by tuning forks : G. Sizes and G. Massol. — 

 The action of the Rontgen rays upon crystallised alumina : 

 F. Bordas. The author has described in previous papers 

 the .Tlteration of colour produced in various forms of 

 crystallised alumina bv the action of the ravs from radium 



