•28 



NATURE 



[April 26, 1900 



hyde. — A rotating contact breaker, and some arrangements for 

 producing powerful high frequency currents, by M. d'Arsonval. 

 A description of the apparatus used in the decoration of the 

 front of the electricity section at the Paris Exhibition. The 

 condenser was of a special type, micanite plate immersed in 

 petroleum being used ; glass, ebonite, celluloid and paraffined 

 paper were all found to be rapidly destroyed by the currents 

 in use. A new device for breaking the circuit by blowing out an 

 arc is also described. — On the Stigmaria, by M. Grand' Eury. The 

 observations of the author are opposed to the view that the 

 Stigmaria are the roots of Sigillaria, a study of over one hundred 

 specimens showing distinct differences between the two kinds of 

 roots. The true Stigmaria^ although frequently found together 

 with the roots of Sigillaria, appear to have lived generally in 

 much deeper waters. — Influence of periodic perturbations of 

 semi-major axis upon the value of the meaii motion deduced 

 from the observations of a planet, and on the corresponding cor- 

 rection of the value originally adopted for the semi-major axis, 

 by M. A. Gaillot.— On a simplified formula for calculating 

 astronomical refractions, by M. L. Cruls. — On series of rational 

 fractions, by M. Emile Borel. — On the characteristics of partial 

 differential equations and the principle of Huygens, by M. J. 

 Coulon. — Vortex motions with cellular structure. Optical study 

 of the free surface, by M. Henri Benard. — The increases of re- 

 sistance in radio-conductors, by M. lidouard Branly. The 

 usual effect observed in receivers for the Hertzian waves is a de- 

 crease of resistance. In certain cases, however, the opposite is the 

 case, and the experimental results for a tube containing lead per- 

 oxide are given. — Induction and electrostatic oscillations, by M. 

 P. de Keen. — Remarks on a recent note of M. G. le Bon, by 

 M. P. Curie. The property of losing its luminosity possessed 

 by a radiferous barium chloride, recently made the subject of a 

 communication by M. le Bon, has been previously published by 

 several authors. — A new microchemical reaction of palladium, 

 by MM. M. E. Pozzi-Escot and H. C. Conquet. Potassium 

 nitrite and excess of a caustic alkali give characteristic crystals 

 with a solution of a palladium salt. — Experimental researches 

 on the physiological phenomena accompanying chlorosis in the 

 vine, by M. Georges Curtel. Chlorosis is accompanied in the 

 diseased leaf with a marked decrease in the respiratory activity 

 and diminution of the ratio COg : Oj, by a diminution or ces- 

 sation of assimilation, and by a great decrease in the trans- 

 piratory function. — On a Selaginella from the coal-measures of 

 Rlanzy, by M. R.Zeiller.— Subdivisions of the Senonian in 

 Portugal, by M. Paul Choffat.— On the production of calcium 

 carbide, by M. L. K. Bohn. 



DIARY OF SOCIETIES. 



THURSDAY, April 26. 

 Royal Imstitution, at 3.— A Century of Chemistry in the Royal Insti 



tution : Prof. J. Dewar, F.R.S. 

 Institution op 1£i,8ctrical Engineers, at 



mission of Power : Prof George Forbes, F.R.S. 

 Institution OF Mechanical Engineers, at 



Prof. Hele-Shaw, F.R.S. 



—The Electric Trans- 

 — Road Locomotion : 



FRIDAY, April 27. 



Royal Institution, at 9.— Nineteenth Century Clouds over the Dy- 

 namical Theory of Heat and Light : Lord Kelvin, G.C.V.O., F.R.S. 



Physical Society (Solar Physics Observatory, Exhibition Road, South 

 Kensington), at 8.— A short account of the Physical Problems now being 

 investigated at the Solar Physics Observatory, and their Astronomical 

 Applications: Sir Norman Lockyer, K.C.B., F.R.S.— Weather permit- 

 ting, the 36-inch, lo-inch, and g-inch telescopes will be used for the ob- 

 servation and photography of celestial objects and their spectra. The 

 App5-Spottiswo:)de coil and 21-ft. Rowland grating will also be in opera- 

 tion. 



SATURDAY, April 23. 



"Royal Imstitution, at 3.— Egypt in the Middle Ages: Prof. Stanley 

 Lane-Poole. 



MONDA Y, April 30. 



Royal Geographical Society, at 8.30.— Through Africa from the Cape 

 to Cairo : Ewart S. Grogan. t, • , . 



Institute of Actuaries, at 5.30.— Census-Taking : Ur. Keginaia 

 Dudfield. 



TUESDAY, May T. 



Royal Institution, at 3.— Studies in British Geography: Dr. H. R. 

 WEDNESDAY, M.\y 2. 



ENTOMOLOGICAL SOCIETY, at 8. 



Society of Public Analysts, at 8. 



THURSDA Y, May 3. 



Royal Institution, .it 3. — A Century of Chemistry at the Royal Insti- 

 tution : Prof. J. Dewar, F.R.S. 



Linnean Society, at 8. — Note on the Movements in Fishes : Prof. R. J. 

 Anderson. — On New Species of //^a/z/w^rfa, from Funafuti; Miss E. S. 

 Barton.— On West Indian Fungi: Miss A. L. Smith. 



Chemical Society, at 8.— Brazilin, Part IV.: A. W. Gilbody, W. H. 

 Perkin, jun., and J. Yates.— Hsematoxylin, Part V. : W. H. Perkin, 

 jun.,and J. Yates —The Substituted Nitrogen Chlorides and Bromides 

 derived from o- and ;»-acettoluide and their Relation to the Substitution of 

 Halogens in Toluides and Toluidines : F. D. Chattawayand K. R. P. 

 Orton. 



RoNTGEN Society, at 8.— Demonstration and Exhibition of NewM' thods 

 and Results. 



Institution of Electrical Engineers, at 8. — If the discussion on 

 Prof. Forbes's Paper, read on April 26, is concluded, the following Paper 

 will be read :— The Calculations of Distributing Systems of Electric 

 Traction under British Conditions : H. M. Sayers. 



FRIDAY, May 4. 



Royal Institution, at 9 — Potterv and Plumbism : Prof T. E. Thorpe, 

 F-R-S. 



Cold Storage and Icf, Association (Examination Hall, Victoria Em- 

 bankment), at 11.30.— Recent Researches in Refrigeration : G. Halliday. 



—Insulation and Insulators : W. D. A. Bost. At 3.— Electric Lighting 



of Cold Stores : W. B. Esson.— The Design and Construction of Build- 

 ings for Ice Factories and Cold Storage : P. Gaskell. 



SATURDAY, May 5. 

 Royal Institution, at 3. — Egypt in the Middle Ages: Prof. Stanley 

 Lane-Poole. 



CONTENTS. PAGE 



The Birds of Celebes 605 



Pumping in Mines. By Prof. W. Galloway .... 606 



The Palaeontology of the Invertebrata 608 



Inadequacy of the Cell-Theory. By J. A. T. . . . 609 

 Our Book Shelf:— 



Renard and Stober : "Notions de Mineralogie."— 



H. A. M 610 



" Muret- Sander's Encyclopaedic linglish- German and 



German- English Dictionary" . 610 



Hertwig : " DieElemente der Entwickelungslehredes 

 Menschen und der Wirbelthiere."— E. A. M. . . 610 

 Letters to the Editor:— 



Recent Exploration in the Upper Air and its Bearing 



on the Theory of Cyclones.— H. H. Clayton . . 611 

 Rock-structures in the Isle of Man and in South 



Tyrol.— G. W. Lamplugh 612 



Electric Light Wires and Dust. — A. A. C. Swinton 612 

 On the Size at which Heat Movements are mani- 

 fested in Matter. By Prof. Geo. Fras. FitzGerald, 



F.R.S 612 



Report of the Malaria Expedition to Sierra Leone 614 

 Joseph Bertrand. {With Portrait.) By Prof. G. H. 



Bryan, F.R.S 614 



Notes 616 



Our Astronomical Column: — 



Astronomical Occurrences in May 621 



Photographs of the Aurora Spectrum 621 



New Variable Star in Taurus 621 



New Variable in Cassiopeia 621 



Formula for Atmospheric Refraction 621 



Determination of Axis and Compression of Neptune . 621 

 The Relations between Electricity and Engineer- 

 ing. By Sir William Henry Preece, K.C.B., 



F.R.S 622 



The Significance of the Increased Size of the 

 Cerebrum m Recent as compared with Extinct 

 Mammalia. By Prof. E. Ray Lankester, F.R.S. 624 



Zones in the Chalk 625 



University and Educational Intelligence 625 



Scientific Serials ^^6 



Societies and Academies 627 



Diary of Societies ^^8 



NO. T59I, VOL. 61] 



