April lo, il 



NA TURE 



567 



group but feebly developed in this region. — Mr. R. Bowdler 

 Sharpe read the description of three rare species of Flycatchers, 

 viz. Alseonax minima, Lioptihis abyssitsiciis, and Liopt lus 

 galinieri. Mr. Sharpe also described an apparently new species 

 of Nuthatch discovered by Mr. John Whitehead in the moun- 

 tains of Corsica, and proposed to be called Sil/a 'juhitcheadi — 

 Mr. G. E. Dobson, F.R.S., read a paper on the myology and 

 \-isceral anatomy of CaPromys melnmirus, of which rare mammal 

 specimens had been lately obtained for him by Mr. F. W. 

 Ramsden, H.M. 's Consul at St. Jago de Cuba. The well- 

 known division of the hepatic lobes into minute lobules in 

 C. pilorides from the same island was shown not to exist in 

 C. melanuriis, which otherwise closely resembled the fonner 

 species, and this character could therefore no longer be considered 

 a generic one. 



Edinburgh 



Royal Society, March 3. — Sir W. Thomson, hon. vice- 

 president, in the chair. — Sir W. Thomson communicated a paper 

 on the efficiency of clothing for maintaining temperature, lie 

 showed that if a body be below a certain size, the effect of 

 clothing will be to cool it. In a globular body tlie temperature 



will only be kept up if the radius be greater than — , where k 



2 e 

 is the conductivity of the substance and c its emissivity. — Prof. 

 I. Thomson read a paper on the law of inertia, the principle of 

 chronometry, and the principle of absolute clinural rest and of 

 ab.solu'e rotation. In this paper the author proceeded to dis- 

 criminate betW'Cen what men -can know, and what men cannot 

 know, as to rest and motion in unmarked space. For example, 

 men have no means of knowing or imagining whether a ball 

 existing in space is in motion or at rest ; nor have they any 

 means, if it be in motion, of knowing or imagining any one 

 direction, rather than amther, as being the direction of the 

 straight line from the place that was occupied by it-^ centre at 

 any past instant to the place occupied by that centre at pre-ent. 

 There is then an essential difficulty a^ to our forming a distinct 

 conception either of rest or of rectiiiuear motion through un- 

 marked space. He discussed, in connection with this, the state- 

 ment set forth by Sir Isaac Newton, under the designation of 

 the first law of motion, that every body contimtes in its state of 

 resting or of moving uniformty in a stfaight line, except in so 

 muc/i as, by applied forces, it is compelled to change that state. A 

 most important truth in the mture of things, perceived with more 

 or less clearness, was, he said, at the root of that enunciation ; 

 but the word--, whether taken by themselves, or in connecti';n 

 with Newton's accompanying definitions and illustrations, were 

 inadequate to give expression to that great natural truth. He 

 proceeded to explain the character of mutual motions, which 

 can in any sense be regarded as uniform rectilinear mutual mo- 

 tions. He gave, under the title of the law of inertia, an enuncia- 

 tion which he offered as setting forth, by a better expression, all 

 the truth which is either explicitly stated, or is suggested by the 

 first and second laws of motion in Sir Isaac Newton's arrange- 

 ment. In connection with the law of inertia he gave further 

 statements bringing out expressions of the principle of chrono- 

 metry and the principle of " directional fixedness " or of absolute 

 clinural rest, and of absolute rotation. — Sir W. Thomson 

 described a modification of Gauss's method for determining the 

 horizontal component of terrestrial magnetic force and the mag- 

 netic moments of bar magnets in absolute measure. — Mr. 

 Thomas Muir gave a paper on the phenomenon of greatest 

 middle in the cycle of a class of periodic continued fractions. 



March 17. — Robert Grey, vice-president, in the chair. — 

 Messrs. Peach and Home, of the Geological Survey of Scotland, 

 communicated a paper on the Old Red Sandstone volcanic rocks 

 of Shetland. — Mr. P. Geddes gave the first two parts, mathe- 

 matical and physical, of a paper on the principles of economics. 

 — Prof. Crum Brown communicated a paper by Prof Michie 

 Smith on an integrating hygrometer. 



Dublin 

 University Experimental Science Association, March 

 l8. — On the boiling-points of the haloid ethers, by F. Trouton. 

 — On a new test for g.allic acid, by A. E. Dixon, B. A. The 

 crimson-red colour which Dr. Sidney Young had noticed on 

 adding a solution of cyanide of potassium to a solution of gallic 

 acid, and which a few minutes' rest or gentle warmth causes 

 completely to disappear, is probably due to oxidation. For 

 although when shaken in contact with the air the colour reap- 



pears, it will not do so when shaken in an atmisphere of hydro' 

 gen, nitrogen, or carbon dioxide. On re-expisure to the air, with 

 agitation, the colour may be Ijrought back. The red coliuris 

 not dissolved out by .alcoh d, ether, or chloroform ; neither does 

 it afford any characteristic absorption-spectrum. — On Ayrton 

 and Perry's electrometers, by G. F. Fitzgerald, F.R.S.— An 

 eleclrj-mngnet for use in analysis was exhibited by J. Joly, 

 B E. The electro-magnet is sealed into a test-tube to enable it 

 to be dipped into sohrions c:>ntxining perruginous particles. 



Paris 

 Academy of Sciences, March 31. — M. Rolland in the chair. 

 — Remarks on the third volume of tlie "Annals of the Bureau of 

 Longitudes," presented to the Academy by M. Faye. — On a pro- 

 posed classification of comets according to their direct or retrograde 

 motion, by M. Faye. — Note on the form of the nucleus of the Pons- 

 Brooks comet, by M. Faye. — On the specific heat of gaseous ele- 

 ments at very high temperatures, by MM. Berthelot and Vieille. 

 — Note on the origin of sugar of mill;, by M. Paul Bert. From 

 experiments made on goats the author infers that the sugar of 

 milk is produced by the mammary secretion of the superabundant 

 sugar formed by the organisms after parturition, most probably in 

 the liver. — On anew species of fossil Sirenian found in the Paris 

 Basin, by M. A. Gaudry. — On the correspondence between 

 two different species of functions of two systems of quantities 

 correlated and equal in number, by M. Sylvester. — Separation 

 of gallium ; separation from organic substances, by M. Lecoq 

 de Boisbaudran. — On a modified form of lightning-conductor, 

 by M. A. Callaud. — Results of experiments with a new venti- 

 lating system worked by centrifugal force, by M. L. Ser. — Ob- 

 servations made at the Meudon Observatory on the planet Mars, 

 by M. E. L. Trouvelot. — Approximate calculation of the thrust 

 and surface of fracture in a homogeneous horizontal mass of 

 earth supported by a vertical wall, by M. J. Boussinesq. — On 

 Gylden's differential equation : — 



~ = i^o + -^ <f 1 + ■»■" "J)? + • • • + X'" <p,„ + . . . 

 a t~ 



in which the cfi's are trigonometrical series, by M. Poincare. — 

 Distribution of the potential in a rectangidar plate traversed by 

 an electric current with permanent regime, by M. A. Chervet. — 

 On the electric phenomenon of the transport of ions and its rela- 

 tion to the conductivity of saline solutions, by M. E. Bouty. — 

 On the resistance of the carbons employed in the electric light of the 

 French lighthouses, by M. F. Lucas. — Note on the verification of 

 the laws of transverse vibration in elastic rods, by M. E. Mercadier. 

 — The general theory of dissociation deduced from the general data 

 furnished by the mechanical theory of heat, by M. Isambert. — 

 Note on the measurement of the tension of dissociation in the 

 iodide of mercury, by M. L. Troost. — On the phenomenon of the 

 crystalline superheating of sulphur, by M. D. Gernez. — On the 

 non-existence" of the hydrate of ammonium, by M. D. Tommasi. 

 The author's experiments lead him to the conclusion already 

 arrived at by Thomsen, that hydrate of ammonium does not 

 exist in ammoniac water. — On the decomposition by water of the 

 combinations of cupreous chloride with the chloride of potassium 

 and chlorhydric acid, by M. H. Le Chatelier. — On the compo- 

 sition of pitch-blende, by M. Blomstrand. From his analysis 

 the author concludes that this substance is a mixture of uranine, 

 silicates, carbonate of lime, and sulphuret of iron, its formula 

 being : — 



aUyPblOcUs) -I- SlRaOjSi, 2Aq) + ylCaO^CO) -I- \ Fe^Sg. 

 — Note on the quantitative analysis of the phosphoric acid in ar.able 

 lands, by M. G. Lechartier. — Heat of formation of the fluoride 

 of silver, of magnesium, and of lead, by M. Guntz. — Thermo- 

 chemical study of hydrofluosiliceous acid, by M. Ch. Truchot. — 

 On the glyoxalbisulphide of soda, by M. de Forcrand. — On the 

 influence of cerebral lesions on the temperature of the body, by 

 M. Ch. Richet. — On the special distribution of the motor roots 

 of the brachial plexus in the human system, by MM. Forgue 

 and Lannegrace. — Description of a gigantic Dictyoneura [D. 

 monyi) found in the Carboniferous measures of Commentry 

 (Allier), by M. Ch. Brongniart. This remarkable insect must 

 have been at least fifty centimetres long. — On the origin of the 

 roots in the ferns, by M. Lachmann. — On the causes which may 

 modify the effects of the action of light in directing the motion 

 of plants, by M. E. Mer. — On the diffusion of christianite in the 

 ancient lavas of the Puy-de-D6me and the Loire Basin, by M. 

 F. Gonnard. — Note on the origin of certain phosphates of lime 

 found in mass in the limestones of the Secondary scries, and of 



