48 



NATURE 



[May lo, 1500 



by Prof. Beyerinck, Prof. Hoogevverff and Mr. ler Meulen 

 prepared pure indican from leaves o{ Polygoujim tiiictoritim, 

 cultivated by Prof. Beyerinck, and from indican solutions 

 received from Mr. Hazewinkel. Indican crystallises out of an 

 aqueous solution with 3 mol. H2O, probably in rhombic crystals, 

 melting at 51° and decomposing, when heated, to a higher 

 temperature with the formation of violet vapours ; it tastes bitter 

 and is optically active, exerting a left-handed rotation. Over 

 sulphuric acid in vacuo it loses its water of crystallisation ; its 

 melting point is then ioo°-i02°. It dissolves pretty readily in 

 water, methyl alcohol, ethyl alcohol and acetone, and very 

 slowly in benzole, carbon disulphide, ether or chloroform. It 

 is represented by the formula C]4Hi7NOb, corresponding to the 

 formula proposed by Marchlewski. The result obtained was 

 567 per cent. C, 5'8 per cent. H, 47 per cent. N ; the molecular 

 weight was determined cryoscopically. On decomposition 

 with HCl and oxidation with air, indican yielded indirubinous in- 

 digotine. No difference was observed between indican out oi In- 

 digofe>a leaves and that obtained from Polygonwn leaves. Further 

 investigations were promised. — The following pai)ers were 

 al.so presented for publication in the Froceedings : On a special 

 case of Monge's difiPerential equation, by Prof. W. Kapteyn. — 

 On the locus of the centres of hyperspherical curvature for the 

 normal curves of ^-dimensional hyperspace, by Prof. Schoute. — 

 On the power of resistance of the red-blood corpuscles, by Mr. 

 Hamburger. — (i) On behalf of Mr. J. D. van der Waals, junr., 

 a paper on equations, containing functions for different values of 

 ■the independent constant ; (2) on behalf of Dr. J. Verschaffelt, 

 a paper on the critical isotherm and the densities of saturated 

 vapour and liquid in the case of isopentane and carbonic acid, 

 t)y Prof, van der Waals. — On the 14-monthly period of the 

 •motion of the earth's pole, with determinations of the azimuth of 

 ! the meridional signs of the Leyden Observatory in the years 

 4882-1896, by Prof. H. G. van de Sande Bakhuyzen, on behalf 

 of Mr. J. Weeder. — Prof. Hoffman presented for publication in 

 Ihe Transactions a paper, entitled " Zur Entwicklungsgeschichte 

 der Sympathicus." 



DIARY OF SOCIETIES. 



THURSDA K, May to. 

 1 R WAt. SociKTV, at 4.30.— On the DiflFusion of Gold in Solid Lead at the 

 Ordinary Temperature: Sir W. Roberts-Austen, F.R.S.— On Certain 

 Properties of the Alloys of Gold and Copper : Sir W Roberts-Austen, 

 F.R.S., and Dr. T. K. Rose.— Experiments on the Value of Organic 

 Sensation as Contributory to Emotion: Prof. Sherrington, F.R.S.— On 

 the Brightness of the Corona of April 16, 1893. Preliminary Note : Prof. 

 Turner, F.R.S.— The Radio-Activity of Uranium : Sir W. Crookes, 

 F.R.S. 



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

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



Mathematical Society, at 5.30 —Special Meeting. — The Djfferential 

 Equation whose solution is the Ratio of Two Solutions of a Linear Dif- 

 ferential Equation : M. W. J. Fry.— A Congruence Theorem relating to 

 Eulerian Numbers and other Coefficients : Dr. Glaisher, F.R.S.— Linea.r 

 Substitutions Commutative with a given Substitution : Dr. L. E. 

 Dickson. 

 "Institution of Electrical Engineers, at 8.— A Frictionless Motor 

 Meter : S. Evershed. 



iIron and Steel Institute, at 10.30.— Ingots for Gun Tubes and Pro- 

 peller Shafts : F. J. R. CarruUa.— The Manufacture and Application of 

 Water-Gas : Carl Dellwik.— The Equalisation of the Temperature of 

 Hot Blast : Lawrence Gjers and Joseph H. Harrison.— The Manganese 

 Ores of Brazil : H. Kilburn Scott.— The Utilisation of Blast-furnace 

 -Slag : Ritter Cecil von Schwarz (Li6ge). 



FRIDAY, Utci II. 



Royal Astronomical Society, at 8.— On the Alleged Rotation of the 

 Spiral Nebula M 51 Canum Venat : H. H. Turner.— Observations of 

 Minor Planets at Windsor, New South Wales : John Tebbutt.— The 

 Duration of the Greater Sun-spot Disturbances for the Years 1881 to 

 1899: Rev. A. L. Cortie.— Note on Measures by Prof. Barnard of Two 

 Standard Points on the Moon's Surface : S. A. Saunder.— Micrometrical 

 Measures of Double Stars : W. Coleman.— Diagrams for Planning Photo- 

 graphic Observations of Eros: A. R. Hinks. 



Ph vsical Society, at 5. — Discussion of Prof Lodge's Paper on the 

 Controversy concerning Volta's Contact Force. — The Heat of Formation 

 of Alloys : Mr. J. B. Tayler.— On the Want of Uniformity in the Action 

 o( Copper-Zinc Alloys on Nitric Acid: Dr. Gladstone, F.R S.— An 

 Electromagnetic Experiment, and Experiments illustrating the Aberra- 

 tion called Coma : Prof. S. P. Thompson, F.R.S. 



Malacological Society, at 8.— On a New Species oi Despoena, Newton 

 (^Proserpina, Gray) : with Notes on some Allied Forms : E. R. Sykes.— 

 On some New MoUusca from the Philippines : G. B. Sowerby.— On some 

 Lamellibranch Remains occurring in a Sandstone from the Malay 

 Peninsula: R. Bullen Newton. 



SATURDAY, May 12. 

 Royal Institution, at 3.— South Africa : Past and Future: Dr. Alfred 

 P. Hillier. 



NO. 1593 VOL. 62] 



MONO A Y, May m. 

 -The Incandescent Gas Mantle and 



Use: 

 Nature and Man in British 



Royal Geographical Society, at 8.30. 

 New Guinea : Prof. A. Haddon, F.R.S. 



TUESDAY, May 15. 

 Royal Institution, at 3. — Brain Tissue considered as the Apparatus of 



Thought : Dr. Alex Hill. 

 Anthropological Institute, at 8.30 

 Royal Statistical Society, at 5. — Municipal Finance and Municipal 



Enterpri.se : Sir H. H. Fowler. 



WEDNESDAY, May 16. 

 Society of Arts, at 8. — A National Repository for Science and Art: 



Prof. Flinders Petrie. 

 Royal Meteorological Society, at 4.30. — The Wiltshire Whirlwind 



of October •!, 1899 : the late G J. Symons, F.R.S.— The Variations of the 



Climate of the Geological and Historical Past and their Causes: Dr 



Nils Ekholm. 

 Royal Microscopical Society, at 7.30.— Exhibition of Micro.scopic 



Pond Life. At 8. — On the Lag in Microscopic Vision : E. M. Nelson. 



THURSDAY, May 17. 

 Royal Society, at 4.30. 



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

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

 Zoological Society, 314.30. — The Freshwater Fishes of Africa : G. A. 



Boulenger, F.R.S. 

 Society of ARTs(Indi.in Section), at 4.30. — The Industrial Development 



of India : J. A. Baines. 

 Institution of Electrical Engineers, at 8. — Alternating Current 



Induction Motors : A. C. Eborall. 

 Chemical Society, at 8. — Chlorine Derivatives of Pyridine. VI. The 



Orientation of some Aminochloropyridines : W. J. Sell and F. W. 



Dootson. 



FRIDAY, May 18. 

 Royal Institution, at 9. — The Structure of Metals: Prof. J. A. Ewing, 



F.R.S. 

 Epidemiological Society, at 8.30. 



SATURDAY, May 19. 

 Royal Institution, at 3.— South Africa : Past and Future : Dr. Alfred 



CONTENTS. PAGE 



Mechanism, Idea, or— Nature ? By H. W. B. . . 25 

 The Evolution of European Peoples. By Prof. A. C. 



Haddon, F.R.S 27 



A Revision of Certain Cell Problems. By Prof. 



J. B. Farmer 28 



Modern Power Looms 29 



Our Book Shelf:— 



Wallon : " Le9ons d'Optique geometrique a I'Usage 



des Eleves de Mathematiques speciales." — E. E. . 30 

 Hedley : "Therapeutic Electricity and Practical 



Muscle Testing " 3° 



Atkinson: " Lessons in Botany " . ...... 30 



Barnes: "Outlines of Plant Life, with special refer- 

 ence to Form and Function " 30 



Letters to the Editor:— 



Note on some Red and Blue Pigments. — Prof. 



T. D. A. Cockerell 31 



Valve Motionsof Engines.— F.J. Vaes ; Prof. John 



Perry, F.R.S .^ . 31 



Drunkenness and the Weather.— Dr. Edwin G. 



Dexter . 31 



Some Speculations as to the Part played by Cor- 

 puscles in Phystcal Phenomena. By Prof. J. J. 



Thomson, F.R.S. . 3' 



Science in Relation to Art and Industry ...... 32 



Notes dl 



Our Astronomical Column: — 



Comet Giacobini (1900 a) 37 



Colour Screens for Refracting Telescopes 37 



Photometric Revision of Harvard Photometry .... 37 

 Fitz Gerald's " Highest Andes." {Illustrated.) By 



Edward Whymper . 3^ 



Pottery and Plumbism 42 



Applications of Electrical Science. By Prof. G. F. 



Fitzgerald, F.R.S 43 



University and Educational Intelligence 45 



Societies and Academies 46 



Diary of Societies 48 



