72 



NATURE 



[November i6, 1S93 



similar American Clemens joint. — On a class of differential 

 equations whose general integral is uniform, by M, Emile 

 Picard. — Sigr.i.icance of the variety of organs in the gradation 

 of vegetable species, by M. Ad. Chatin. — On a Nymphaea bed 

 recently found and explored in the Aquitanian of Manosque, 

 by M. G. de Saporta. — On equations of the second order with 

 fixed critical points, and univocal correspondence between two 

 surfaces, by M. Paul Painleve. — On certain ordinary differential 

 equations, by M. Alfred Guldberg. — On certain families of 

 gauche cubes, by M. Lelieuvre. — On the nature of the reflection 

 rif electric waves at the end of a conducting wire, by MM. Kr. 

 Blrkeland and Ed. Sarasin. — Observations upon the preceding 

 communication of MM. Birkeland and Sarasin, by M. H. 

 Poincare. This is an application of Maxwell's theory to the 

 phenomena of propagation of energy into space round the end 

 of a conducling wire along which electric waves are passing. 

 It is shown that the deductions from the theory are in general 

 accord with the facts observed. — On the measurement of co- 

 efficients of induction, by M. H. Abraham. The employment 

 of a differential galvanometer in these measurements permits of 

 an accurate determination within i percent., and a reading to 

 within o'l per cent, without much difficulty. The induced 

 currents from a commutator regulated by a stroboscopic method 

 are sent through one circuit of a differential galvanometer, the 

 deflection being compensated by a continuous current derived 

 from the same battery. The commutator is then stopped, and a 

 current equivalent to the induced current is derived from the 

 primary circuit through a resistance r, and sent through the 

 secondary circuit, r being chosen so as to establish equilibrium 

 in the differential galvanometer. Then this actual resistance r 

 may be put equal to the fictitious resistance nM. obtaining while 



induction was going on, and we have M = ^ where M is theco- 



n 



efficient of mutual induction, and n the frequency of the com- 

 mutator. The resistance r may be constituted by a standard 

 ohm coil. M. Abraham has found by this method that 

 ihe coefficient of mutual induction is reciprocal in 

 the case of two circuits free from iron, but that this reciprocity 

 is disturbed if they contain iron cores. — On vision of opaque 

 objects by means of diffracted light, by M. Gouy. If an opaque 

 and non-reflecting object is examined by means of a microscope 

 or telescope, the object being placed in the path of a beam of 

 light, the image is formed both by the rays following 

 geometrical paths and by those diffracted by the outlines of 

 the object. If the former are intercepted, the diffracted rays 

 only form the image. This may be done by placing a small 

 screen at the focus of the object-glass inside the telescope, so as 

 to intercept the rays from a very distant source which converge 

 there. The outline of the object is then seen as a thin bright 

 line on a dark background, and with sufficient enlarging power 

 this line is seentoconsist oftwo,very close together, and separated 

 by a very sharp black line. This black interval disappears on 

 intercepting the diffracted rays either inside or outside the 

 geometrical shadow, thus showing that it is due to the inter- 

 ference of these two beams. They possess a difference of phase 

 nf half a wavelength, and equal amplitudes. An arrangement 

 such as this may prove useful when the outlines of an object re- 

 quire to be sharply defined. — On a new method of preparing methy- 

 Inmine and on the constitution of hexamethylene-tetramine, by 

 MM. A. Trillatand Eayollat. — On the alkaline methyl-tartrates 

 and ethvl-tartrates, by M. J. Fayollat. — Researches on the homo- 

 logues of gallanilide ; preparation ofgalloparatoluide, by M. P. 

 Cazeneuve. — Experimental hereditary influences, by MM. Gley 

 and Charrin. — On a phenomenon of inhibition in Cephalopoda ; 

 paralytic constriction of chromatophores, by M. C. Phisalix. — 

 r»n the serial craniological continuity in the genus Lepus, by 

 M. Remy Saint-Loup. — On the genus Polydora Bosc {Leiicodore 

 Johnston), by M. F. Mesnil. — The Callibrachion, a new 

 reptile of the Permian of Autun, by MM. M. Boule and Ph. 

 Glangeau. — On the glacial and erratic phenomena in the 

 Cachapoal Valley (Andes of Chili), by M. A. F. Nogues. The 

 phenomena of transport by water and glaciers have contributed 

 to the formation of the erratic system in the valleys of the Chili 

 Andes. There must have existed lakes or deep terrace ponds. 

 The glaciers must formerly have descended further than they 

 do at present, and at the Cachapoal they are actually retreating 

 now. — An earthquake shock at Grenoble, by M. Kilian. This 

 happened at 4h. 13m. 40s. A.M., Paris time, on November 5, in 

 a direction from N. to S., and was recorded by the seismometer 

 of the Geological Laboratory of the Faculty of Sciences. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED 



Books.— Social Eng!.^nd : edited by H. D. Traill, vol. i. (Cassell).— Xew 

 Technical Educator, vol. ii. (Cassell). — Guelphs and Ghibellines : O. Brown 

 in? (Methuen).— Intensity Coils, 18th edition (Perken). The Magic Lan- 

 tern, 2nd edition (Perken). — British Fungus Flora: G. Massee, vol. 3 (Bell), 

 — Weather Lore: compiled, &c., by R. Inwards (Stock). — Les Courants 

 Polyphases : J. Rodet et Busijuet (Paris, Gauthier-Villars). — Pour Devenir 

 Financier: R. Chevrot (Paris, Gauthier-Villars).— Golf : a Royal and 

 Ancient Game : edited by R. Clark, 2nd edition (Macmillan). — Aberration 

 Problems: Prof. O. J. Lodge (K. Paul).— Eighth Annual Report of the 

 Bureau of Ethnology : J. W. Powell (Washington). — Diamonds and Gold in 

 South Africa : T. Reunert (btanford). — The Incandescent Lamp and it.s- 

 Manufacture : G. S. Ram (" Electrician" Co.). — Eine Botanische Tropen- 

 reise. Prof. Dr. S. Haberlandt (Leipzig, Engelmann). — Der Botanische 

 Gaiten "'s Lands Plnutentuin " zu Buitenzorg auf Java (Leipzig, Engel- 

 mann). — Grundziige der Physiologischen Psychologie : Prof W. Wundt, 

 Zweiter Band (Leipzig, Engelmann). — Die Allmacht der Naturiiichtung : 

 Prof. A. Weismann (Jena, Fischer). — Australasia, vol. i. : — Australia and 

 New Zealand: Dr. A. R._ Wallace (Stanford). 



Pa.mphlets. — Fenomeni Geodinamici che precedettero, accompagnarono 

 e Seguirono I'eruzione Etnea del Maggio Guigno i8£6, S. Arcidiacono.- 

 Electro-Cultur? : P. de Puydt (Bruxelles). — Ethnography of the Ara» 

 Islands, Co. Galway, A. C. Haddon, and C. 'R. Biowne (Dublin). — 

 Bibliography of the Chinookan Languages : J. C. Pilling (Washington). — 

 Catalogue of a Stratigraphical Collection o Canadian Kocks prepared for 

 the World's Columbian Exposition, Chicago 1893 : W. F. Ferrier (Ottawa), 

 — Das Karstphiinomen : Dr. J. Cvijic (Wien, Hulzel). — Uie Biologie ali» 

 selbstiindige Grund wissenschaft : H. Driesch (Leipzig, Engelmann). — Tafe! 

 des Integrals : B. Kampfe (Leipzig, Engelmann). — On the Volcanoes and 

 Hot Springs of India: Dr. V. Ball (Dublin). 



Serials. — Kansas University (Quarterly, October (Lawrence, Kansas). — 

 American Journal of Science, November (Newhaven, Conn.). — Bulletins der 

 la Sociit^ d'Anthropologie de Paris. Nos. 8 and 9, 1893 (Paris). — L'Astro- 

 nomie, November (Pans). — Zeitschrift fiir Wissenschafrliche Zoologie, Ivi. 

 Band, 4 He(t (Williams and Norgate). — American Naturalist, October 

 (Philadelphia). — Morphologisches Jahrbuch, 20 Band, 3 Heft (Williams and 

 Norgate). — Physical'Society of London, Proceedings, vol. xii. Part 2 (Taylor 

 and Francis). — American Journal of Mathematics, vol. xv. No. 4 (Baltimore). 

 — Proceedings and Transactions of the Queensland Branch of the Royal 

 Geographical Society of Australasia, vol. 8 (Brisbane). 



CONTENTS. PAGE 



Romanes on Weismann. By P. C. M 49 



Extra-Tropical Orchids. By R. A. Rolfe 50 



Our Book Shelf:— 



Gore: " An Astronomical Glossary " 51 



A Son of the Marshes : " With the Woodlanders and 



By the Tide" 51 



Taylor; " Pitt Press Euclid, V.-VL " 53 



Furneaux ; " The Out-door World, or Young Col- 

 lector's Handbook" 52 



Briggs and Bryan : " Worked Examples in Co-ordinate 



Cieometry" 52 



Letters to the Editor : — 



Sir Henry H. Howorth on " Geology in Nubibus." — 



Dr. Alfred R. Wallace, F.R.S 52 



The Erosion of Rock-Basins.— Prof. T. G. Bonney, 



F.R.S 52 



"The Zoological Record." — R. I. Pocock; F. A. 



Bather ; B. B. Woodwrard 53 



Reco<Tnition Marks.— G.J. Macgillivray ; Dr. Alfred 



R.Wallace, F.R.S 53 



Correlation of Solar and Magnetic Phenomena. — 



William Ellis, F.R.S 53 



The New Bird-Protection Bill 54 



Light-Waves and their Application to Metrology. 



{With Diagrams.\ By Prof. A. A. Michelson . . 56 

 Further Notes and Observations upon the Instincts 

 of some Common English Spiders. By R. I. 



Pocock 60 



Notes 63 



Our Astronomical Column: — 



Brooks's New Comet (1 893(r) 67 



Biela Meteors (^7 



The Planet Jupiter 67 



A New Variable Star 67 



The Observatory for November 67 



Solar Observations at Catania, Rome, &c 67 



The Stigmata of the Arachnida, as a Clue to their 



Ancestry. {With Diagram.) By H. M. Bernard . . 68 



The Present Standpoint of Geography 69 



Some Laboratories of Marine Biology 7° 



University and Educational Intelligence lo 



Scientific Serials 1^ 



Societies and Academies 7' 



Books, Pamphlets, and Serials Received 72 





NO. 1255, VOL. 49] 



