452 



NATURE 



[March 8, 1894 



address concludes with a notice of the rocks of Brittany and the 

 Channel Isles, which have attracted the attention of more than 

 one author. 



Cambridge. 

 Philosophical Society, February 26.— Prof. Hughes, Presi- 

 d-ent, in ihe chair. — The following communications were made: 

 — On current-<-heets, specially on ellipsoids and anchor-rings, 

 by Mr. R. H. D. Mayall. The electric currents induced in 

 thin uniformly conducting sheets of any shape placed in a 

 variaV)'e magnetic field were considered ; and it was shown that 

 they could be determined by the solution of a differential 

 equation of the second order with the aid of the appropriate 

 boundary conditions. Orthogonal curvilinear co-ordinates were 

 u?ed in every case, the equation to the surface of the conductor 

 being got by making one co-ordinate constant. In this way 

 results were worked out for the infinite plane, the sphere, the 

 infinite right circular cylinder, and the ellipsoid with three 

 unequal axes. The case of the anchor-ring was also discussed, 

 and a set of linear equations found to determine the unknown 

 coefficients in the expression (or the current function. These 

 were solved for the particular case when the exciting disturb- 

 ance was represented by a harmonic of the first degree and 

 symmetrical about the axis of the ring ; and a simple expression 

 was found for the modulus of decay of free currents of the same 

 type. — The complete system of quatcrnariants for any degree, 

 by Mr. D. B. Mair. A method is given for finding the con- 

 comitants of a quaternary form of any degree or of simultaneous 

 quaternary forms. The cases of a single quadratic, a single 

 cubic, a single quartic, a system af two quadratics, and a system 

 of three quadratics, are treated at length. — The configuration 

 of a pair of equal and opposite hollow straight vortices, of finite 

 cross-section, moving steadily through a fluid, by Mr. H. C. 

 Pocklington. — On a class of definite integrals connected with 

 Bessel's functions, by Mr, A. B. Basset. 



Paris. 

 Academy of Sciences, February 26. — M. Loewy in the 

 chair. — On the scientific work of Jean Louis Armand 

 de Quatrefages de Breau, by M. Edmond Perrier. — On the 

 equation of the vibrations of a membrane, by M. H. Poincare. 

 — On a way of obtaining a uniform circular movement by 

 means of two vibratory movements, by M. Marcel Deprez. — 

 Observations of the new planet AV (Courty, 1894, February 

 11), made at the Paris Observatory, by MM. O. Callandreau 

 and G. Biyourdan. — On the application of the method of suc- 

 cessive approximations to the ordinary differential equations of 

 the first order, by M. Ernest Lindelof. — Observations on the 

 preceding communication, by M. Emile Picard. — The com- 

 bustion of the ordinary ballistic explosives, by M. P. Vieilie. 

 The old black and brown powders do not show combustion by 

 parallel surlaces, whereas the new colloidal powders give data 

 satisfying exactly the criterion of combustion by parallel sur- 

 faces. — On the fundamental laws of heat, by M. G. Mouret. 

 The three laws concerning, — the conservation of entropy in 

 reversible operations, the conservation of heat in conduction, 

 and the increase of entropy in irreversible operations, appear to 

 be fundamental laws of heat, and not derivable from a more 

 general law. — On a means of compensating the E.M.F. of a 

 hydro-electric pile, by M. J. Schiirr. — Measurement of the dif- 

 ference of phase between two alternating sinusoidal currents of 

 the same period, by M. Albert Hess.^ — Action of heat on 

 the double nitrites of metals of the alkali group and 

 metals of the platinum group : ruthenium com- 

 pounds, by MM. A. Toly and E. Leidie. The formulae 

 Ru2(NO„^e.4KN02 and Ru20(N02)4.8KN02 are now assigned 

 to the piiiassium ruthenium nitrites. At 36o°-440° in a 

 vacuum, explosive decomposition occurs of the latter compound, 

 with the production of nitrogen, nitrogen dioxide, potassium 

 nitrite, and an msoluble black substance, sRugOg.KjO, The 

 preparation and properties of the sodium compounds, 

 Ru2(N02)g.4NaN02-f4H20 and Ru.NO.Cl3.2NaCl are de- 

 scribed. The former yields the compound NajO. 3RU4O9 on 

 healing in sulphur or mercury vapours ; at a red heat l\u02 '^ 

 produced — On the isoiiierism of the nitrobenzoic acids, by M. 

 CEchsner de Coninck. A study of the relative solubilities of 

 theortho-, meta , and para-nitrobenzoic acids in distilled water, 

 dilute alcohol, ether, benzene, light petroleum, carbon bisul- 

 phide, and chloroform is given. — On some derivatives of the 

 oxazine and eurhodine series, by M. Charles Lauth — Analysis 

 of a o:\\\ agtd cheese ; extraction of a new ptomaine, by M, 

 Charle I epietre. A well-crystallised base of the formula 



-> 7 I , VOL. 49] 



C16H24N2O4 has been isolated. It is bitter, inodorous, slightly 

 acid to phthalein, soluble in alcohol but hardly soluble in water, 

 and gives the usual alkaloid reactions but does not yield a tannin 

 precipitate. Its specific rotatory power [o]d = -t- 1 1 '3° in water. 

 It causes diarrhoea, — On some laboratory apparatus, by M. Andre 

 Bidet. — On the odour of benzoic acid (remarks on inodorous 

 substances), by M. Jacques Passy. — Anatomy of the salivary 

 glands of the Philatitida;, by M. Bordas. — On the internal 

 characteristics of the grape, and their utilisation in the deter- 

 mination of species and the distinction of hybrids, by M. Gustave 

 Chauveaud. — Artificial reproduction of awwj-, by M. Stanislas 

 Meunier. — The five days' hurricane, from February 8 to 12, 1894, 

 in Bohemia. A letter from M. Ch. V. Zenger to M. A. Cornu. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Books. — Thermodynamics of Reversible Cycles in Gases and Saturated 

 Vapours: Dr. M. I. Pupin(K. Paul). — The Badminton Library— Big Game 

 Shooting. 2 vols. : C. Phillipps-Wolley, &c. (Longmans). — Philip's Syste- 

 matic Atlas : E. G. Ravenstein (Philip). — Nature Pictures for Little People : 

 M. Mawer, &c. (Sunday School Association). — Le Climat de la Belgique en 

 1893: A. Lancaster (Bruxelles, Hayez). — Man the Primeval Savage: W. G. 

 Smith (Stanford). — Report on North-Western Manitoba: J. B. Tyrrell 

 (Ottawa, Dawson). — Ergebnisse der Meteorologischen Beobachtungen 

 Jahrg. XV. (Hamburg). — A Treatise on Elementary Hydrostatics : J. Greaves 

 (Cambridge University Press). — Joh. Miiller's Lehrbuch der Kosmischen 

 Physik and Atlas to ditto. — Fiinfte umgearbeitete und Vermehrte Auflage : 

 Dr. C. F. W. Peters (Braunschweig, Viewig). — Analytical Geometry for 

 Beginners: Rev. T. G. Vyvyan, Part i (Bell). — Introduction to Elementary 

 Practical Biology: C. W. Dodge(New York, Harper). — Aero-Therapeutics : 

 Dr. C. T. Williams (Macmillan). — Lehrbuch der Petrographie : Dr. F. 

 Zirkel, Zweiter Band (Leipzig, Engelmann). 



Pamphlets. — The Texan Monsoons: M. W. Harrington (Washington). 

 — Die Tropischen Orkane der Siidsee, &c. : E. Knipping (Hamburg). — The 

 Function of Museums, as considered by Mr. Ruskin ; W. White. — Meteor- 

 ology at the Paris Exposition : A L. Rotch. 



Serials. — Geological Magazine, March (K. Paul). — Records of the 

 Botanical Survey of India, Vol. i. Nos. i and 2 (Calcutta). — American 

 Naturalist, February (Philadelphia). — Botanical Gazette, February (Madi- 

 son, Wis.) — Geological Journal, March (Stanford). — Observaciones Mag- 

 neticas y Meteoiologicas del Real Colegio de Belen, Julio-Die. 1889 

 (Habana). — Bulletin of the New York Mathematical .Society, Vol. 3, No. 5 

 New York, Macmill<n). — Science Progress, No- i (Scientific Press).— 

 Quarterly Journal of Microscopical Science, March (Churchill). 



CONTENTS. PAGE 



Electromagnetism and Dynamo Construction. By 



Prof. A. Gray 429 



Internal Combustion Motors. By N, J. Lockyer . 430 



Physiology for Science Schools. By J. S. Edkins . 431 

 Our Book Shelf:— 



Glazebrook : "Light : an Elementary Text-book, Theo- 

 retical and Practical, for Colleges and Schools" . . 432 



Newberry: "Beni Hasan." Part ii 432 



Letters to the Editor :— 



Great Auk's Egg. — ^J. E. Harting 432 



On M. Mercadier's Test of the Relative Validity of 

 the Electrostatic and Electromagnetic Systems of 



Dimensions. — Dr. G.Johnstone Stoney, F. R. S. 432 



Experiments in Elementary Physics. — W. Rheam . 433 

 Spectacles for Double Vision. ( With Diagram.) — 



T. I. Dewar 433 



Recent Local Rising of Land in the North-West of 



Europe. — C. A. Lindvall 433 



Apogamy in Pteris serridata (L. fil.) var. cristata. — 



A. H. Trow 434 



Fireballs. — W. F. Denning 434 



Astronomy in Poetry. — G. W. Murdoch 434 



Recent Publications of the American Geological 



Survey. By Prof. T. G. Bonney, F.R.S 434 



Measurements of Low Vapour Pressures. By J. W. 



Rodger 436 



Notes 437 



Our Astronomical Column : — 



The Aurora of February 28 441 



Mira Ceti 442 



Halley's Comet 442 



Iodine as a Base Forming Element. By A. E. 



Tutton 442 



Prince Henry the Navigator 443 



Science in the Magazines 443 



The Cambricige Diploma in Agriculture 444 



On Homogeneous Division of Space. {Illustrated.) 



By Loid Kelvin, P.R.S 445 



University and Educational Intelligence 448 



S-ientific Serials 449 



Societies and Academies 449 



Books, Pamphlets, and Serials Received 452 



II 



