March 15, 1900] 



NATURE 



4»J 



rounded by neither shell. —Dr. John Henderson communicated 

 a paper on the Clark cell versus the cadmium cell as a standard 

 of electromotive force. In addition to an account of the various 

 modifications of Clark cell which had been made with a view to im- 

 prove it as a satisfactory standard of E.M.F. , and a discussion of 

 the work done by others in regard to the cadmium cell, the author 

 gave a full description of his own elaborate experiments. He 

 experimented on a great variety of modifications ; and his con- 

 clusions were that as regards constancy of E.M.F., smallness of 

 temperature coefficient, power of recovery after being short- 

 circuited, its practical identity though made of materials sup- 

 plied commercially by different manufacturers, and other 

 essential characteristics of a practical standard of electromotive 

 force, the cadmium cell was in all respects superior to the 

 Clark cell. — Dr. Hugh Marshall communicated a short paper 

 on the action of silver salts on solution of ammonium persul- 

 phate, in which he called attention to two striking reactions 

 whi ch he had recently observed and was investigating. When 

 a small quantity of silver salt is added to a strong ammoniacal 

 solution of persulphate, nitrogen'is evolved almost immediately ; 

 the temperature rises rapidly, and the action may soon become 

 violent. Apparently the silver is rapidly peroxidised by the 

 persulphate and reduced by the ammonia. An aqueous solution 

 of ammonium persulphate is steadily decomposed at the ordinary 

 temperature in presence of small quantities of silver salts ; there 

 is no evolution of gas, part of the nitrogen of the ammonium 

 salt being converted into nitric acid, as shown by the equation : 



8(NH4)2S,08 + 6H2O = 7(NH4)2S04 -I- 9H2SO4 + 2HNO3. 

 It was found that, in the space of two to three days a milligram- 

 equivalent of silver salt per litre of solution decomposed one- 

 half of the persulphate originally present, the temperature 

 being 20°. 



Paris. 

 Academy of Sciences, March 3. — Mr. Maurice Levy in the 

 chair. — Remarks by M. Picard on his work on the theory of 

 algebraic functions of two variables. — On the tetrahedral 

 symmetry of the terrestrial globe, by M. de Lapparent. Re- 

 marks on a paper on the same subject by M. Marcel Bertrand. 

 The author thinks that while the original view of Lothian Green 

 groups the main facts of the geography of the earth round a 

 remarkably simple idea, an idea which moreover follows from the 

 principle of least action, the modifications introduced by M. Ber- 

 trand into the original hypothesis have the effect of destroying its 

 simplicity and usefulness. The idea that the effect is due to a 

 slow cooling would also have to be abandoned. — Observations 

 on the preceding note, by M. Marcel Bertrand. A detailed 

 reply to the criticisms of M. de Lapparent. — Preparation and 

 properties of a manganese perfluoride, by M. Henri Moissan. 

 The new fluoride has the composition MUoFg, and is formed by 

 the action of fluorine gas upon manganese iodide. — A tubular 

 furnace, working at any fixed temperature, by M. Armand 

 Gautier. An application of the reverberatory principle to a 

 combustion furnace. — Morphology of the pelvic girdle in 

 Amphibia, by M. Arm. Sabatier. — On the Dinosaurians in the 

 strata of Rognar and VitroUes at the foot of Montagne-Noire, by 

 M. Charles Deperet. — Prof. E. Fischer was elected a Cor- 

 respondant for the Section of Chemistry. — Observations of the 

 Giacobini comet (1900 a) made at the Observatory at Algiers 

 with the 31 "8 cm. equatorial, by MM. Rambaud and Sy.— 

 New determinations of g, by M. J. Collet. A study of the 

 deviations from the normal value in the neighbourhood of a 

 mountain mass. The mean results at Grenoble, Saint-Agreve, 

 and Le Lautaret are given. — On a theory of systems of total 

 differential equations of the second order, by M. Ernst Pascal. 

 — On the electric charge of the deviable rays of radium, by M. P. 

 Curie and Mme. M. P. Curie. The authors prove that that part 

 of the radiation from radium which is deviated in a magnetic 

 field carries a negative charge of electricity, in a similar 

 manner to the kathode rays. Parallel experiments carried 

 out with the Rontgen rays showed similar effects, but to 

 a very slight extent, and the conclusion is drawn that if the 

 X-rays are charged with electricity, they are much more feebly 

 charged than the radium rays. — Disymmetry in the polarised 

 emission of a Geissler tube submitted to the action of a magnetic 

 field, by M. R. Dongier. — On the constitution of the yellow 

 sodium rays, by MM. Ch. Fabry and A. Perot. An application 

 of the interferential spectroscope previously described by the 

 authors. The complicated and variable results obtained by M. 

 Michelson with the D-lines are here shown to be due to the re- 



NO. 1585. VOL. 61] 



versal of the rays. Sodium vapoi^r possesses an enormo«» 

 absorptive power, even at a low temperature and very feeble 

 pressure. — On the spectra of the polar aurora, by M. P&ulsen. — ' 

 On the preparation of the phosphides of iron, nickel, coball and 

 chromium, by M. Georges Maronneau. Phosphide of copper 

 heated in the electric furnace with either of these four metals to 

 a temperature above the boiling point of copper, gives the phos- 

 phide of the metal added, which can be extracted in a pare state 

 by treating the fused mass with nitric acid. The piopefties 

 of FegP, NijP, C02P and CrP are described. — On ei^enol, 

 safrol and propylpyrocatechol, by M. Raymond Delange. 

 The methyl ether of eugenol, reduced with sodium and boil- 

 ing alcohol, gives propylveratrol, which on hydr(Jysis with 

 hydrochloric acid furnishes propylpyrocatechol. — On the diazo- 

 tising of safranine, by M. George F. Jaubert. When diazotised 

 under ordinary conditions the monodiazo-compound is the 

 only product. Both the red mono-acid salt and the blue di- 

 acid salt give the same result, but the green tri-acid salt uses 

 twice as much sodium nitrite, and hence corresponds to an 

 azonium base of orthoquinonoid structure. — The modifications 

 brought about by a longitudinal traction m the stems of plants, 

 by M. Thouvenin. In the plant studied. Zinnia elegans, a 

 moderate longitudinal pull retards the development of the 

 secondary fibro- vascular Ixmdles. — ^Variations in the characters 

 of species of haricots under the influence of grafting, by M. 

 Lucien Daniel. An investigation to determine how far the 

 properties acquired by grafting can be transmitted in the case of 

 an annual, such as haricots, by the seed. It is found that 

 grafting always produces variation in the plants grown iron* 

 seed, this variation being less m.arked in wild species grafted 

 between themselves, and more accentuated in the cultivated 

 plant. — The work of spinal nervoi»s centres, by Mile. J. 

 Joteyko. The nerve may be excited for more than four times- 

 the period producing fatigue in the muscle, without showing 

 signs of fatigue. The spinal nervous centres thus show a very 

 high resistance. — New method of measuring the tactile sensi- 

 bility to pressure of mucous and cutaneous surfaces, by MM. 

 Ed. Toulouse and N. Vaschide. — Concerning the physiolc^ical 

 alternation of the kidneys, by MM. E. Bardier and H. FrenkeL 

 The expeiiments quoted show that there is no real physiological 

 alternation of the kidneys, neither from the point of view of the 

 vaso-motor phenomena nor from that of the flow of uiine. — 

 Hepatic glycogen during pregnancy, by MM. A. Charrinand A. 

 Guillemonat. 



New South Wales. 

 Royal Society, December 6, 1899.— The Piresident^W. M. 

 Hamlet, in the chair. — On the Darwinias of Port Jackson antJ 

 their essential oils, by R. T. Baker and H. G. Smith. The 

 authors show that one of the species of the genus — the shrubj. 

 botanically known as Darwinia fascictilaris, A. Rudge — which 

 occurs plentifully on the sandstone formation around Fort 

 Jackson, is a plant of great commercial importance in regard 

 to its essential oil. This plant belongs to the natttial twfder 

 Myrtaceae, a genus so prolific in oil-yielding species. The oil 

 consists principally of the important ester geranyl acetate, the 

 least amount of this constituent being 567 per cent, and the 

 greatest 65 i per cent., obtained from the oil distiW«d in 

 November. Besides this ester, I3'ii per cent, of U&^ afcohoJ 

 was determined, calculated as geraniol. — On New Soi>th Wales 

 copper ores containing iodine, by Arthur Dieseldorff. Theaalhor 

 (who was on a visit to New South Wales a few years ago) was 

 interested in the discovery of iodine in a sample of cuprire front 

 Cobar by Dr. W. Autenrieth, of the University of Freiberg, 

 Baden. He made further investigations himself as shown fcy 

 the paper, resulting in his proving the presence (A fo^ine m 

 several different samples sent to him from the colony.— Orbit 

 elements Comet I. 1899 (Swift), by C. J. Merfiekl. The oibife 

 elements have been deduced from the observations taken at most 

 of the leading observatories. Sixteen equatior>s of conditiol^ 

 have been employed in finding the corrections to- the assumed 

 parabolic elements. The result of the investigation seems tt> 

 indicate that the geometrical figure described by this comet is an 

 hyperbola. — On the composition of New South Wales labradorite 

 and topazes, with a comparison of methods for the estimationi 

 of fluorine, by G. Harker. The paper gives the composition 

 and properties of a typical labradorite from New Engkad, New 

 South Wales, and also the composition including the water of con- 

 stitution of two varieties of topazes found in New South Wales, 

 one from the Mudgee the other from the New England districts 

 It describes also the results obtained for the percantagp of 



