39^ 



NA TURE 



[August 17, 1905 



ultimate intersections, a correct diagram was obtained 

 of ship waves in deep and broad water, an approximate 

 representation of which had been given in 1887 (see 

 " Popular Lectures and Addresses," vol. iii.). The 

 numerical calculations and drawings were made bv Mr. 

 J. de Graaff Hurster. — On the periods and nodes of Lochs 

 Earn and Trieg : Prof. Chrystal and E. Maclagan 

 Wedderburn. This was a detailed comparison of the 

 observed periods and nodes with those calculated from 

 the hydrodynamical theory as already given by Prof. 

 Chrystal. The bottom contours were appro.ximated to by 

 piecing together appropriate parabolic functions of the 

 depth; the results of theory and of observation w-ere in 

 good agreement, especially as regards the periods, which 

 are less influenced by local conditions than the node- 

 positions or the amplitudes. — .\ regular fortnightly explor- 

 ation of the plankton of the two Icelandic lakes, Thing- 

 vallavatn and Myvatn : C. N. Ostenfeld and Dr. C. 

 Wesenberg-Lund. — Note on the boiling points of solu- 

 tions : S. N. Johnson. It was found that the boiling- 

 point elevation constant C, as calculated from the formula 



C7£/ 1 1 + (;/ - I )a[ = wWV, 

 where m is the molecular weight of salt used, W the 

 weight of solvent, w the w^eight of salt added, a the 

 ionisation constant, n the number of free ions, and 

 c the observed elevation of temperature, had widely 

 differing values. The discrepancies clearly arose from 

 the difficulty of getting the boiling point of the solvent. 

 When, however, C was calculated from the formula 

 when for e and ic are substituted the increments Ac and 

 Aim, as one passes from solution of lower to solution of 

 higher concentration, satisfactorily concordant results were 

 obtained. The salts studied w-ere the nitrate, chlorate, 

 chloride, and bromide of potassium, and the nitrate and 

 chloride of sodium. — The oxidation of manganese by per- 

 sulphates : Dr. Hugh Marshall. — Influence of cross 

 magnetisation on the relation between resistance and 

 magnetisation in nickel : Dr. C. G. Knott. The decrease 

 of resistance of a strip of nickel foil when magnetised 

 transversely to its length was numerically increased when 

 the foil was set in a steady magnetic field magnetising it 

 longitudinally, while the increase of resistance accompany- 

 ing the application of this longitudinal field was 

 numerically decreased when the foil was set in a steady 

 field magnetising it transversely. 

 Paris. 

 Academy of Scienres, August 7. — M. Borquet de la 

 Grye in the chair. — Observations of the planet Y.R. 

 (Goertz) made with the large equatorial of the Observatory 

 of Bordeaux : E. Esclangon. Observations of this 

 planet were made on July 29 and 30, and the results arc- 

 given, together with the mean positions of the comparison 

 stars, and the apparent positions of the planet. — On the 

 sidereal day : .A. Pansiot. — On continued algebraic frac- 

 tions : M. Auric. — On similitude in the motion of fluids : 

 M. Jouguet. — On the state of matter in the neighbour- 

 hood of the critical point : C. Raveau. .-\ criticism on a 

 recent paper on the same subject by MM. G. Bcrtrand and 

 J. Lecarme. The author contests the views put forward 

 by these authors, and notes that a consequence that they 

 have deduced is a peculiarity of which a complete account 

 is rendered by the ordinary kinetic theory of gases. — On 

 magnetic double refraction. Some new active liquids ; 

 .A. Cotton and H. Mouton. .\ solution of dialysed iron 

 prepared by the method of Bravais undergoes a marked 

 change when heated for some time at 100° C. The double 

 refraction in a magnetic field became greater, four hours' 

 heating making the double refraction forty times its 

 original value; the size of the particles was clearly in- 

 creased by the heating. Colloidal solutions of iron were 

 also prepared by the method indicated by Bredig for the 

 precious metals. This solution was doubly refracting also, 

 but the variation with the strength of the field followed 

 a different law to the Bravais solution. A solution of 

 iron prepared by the Bredig method in glycerine was also 

 examined. Solutions were also found exhibiting magnetic 

 double refraction which did not conta'in iron, but minute 

 crystals of calcium carbonate. Reason is shown for sup- 

 posing that for these effects to be observed the size of the 

 separated particles must lie between certain limits. — On 

 the chloroborates of calcium : L. Ouvrard. — Studv of the 



NO 1868, VOL. 72] 



constitution of unsymmctrical dipura-ditolylethane, of the 

 dihydride of 2:7:9: lo-tetramethylanthracene and of 

 2 : 7-dimethylanthracene : James Lavaux. — On the absorp- 

 tion spectrum of manganous salts : P. Lambert. The 

 manganese salts used in the research were purified with 

 especial care from iron, since the spectrum of the latter 

 element in the ultra-violet was found to interfere. A 

 diagram is given of the manganese bands for wave-lengths 

 between 557 and 304. — The thermochemistry of the 

 hydrazones : Ph. Landrieu. The reaction betw-een some 

 ketones and aldehydes has been determined directly in the 

 calorimeter, and the values thus found compared with those 

 deduced from the heats of combustion determined with the 

 Berthelot bomb. The results of the two methods show a 

 fair agreement. — The mechanical properties of iron in 

 isolated crystals : F. Osmond and Ch. Fremont. The 

 experiments were made upon crystals of a volume of 

 several cubic centimetres, and included measurements of 

 the extension, compression, hardness, and bending. It 

 was found that the mechanical properties of iron in crystals 

 are a function of the crystallographic orientation. Thf 

 fragility, very great in the plane of cleavage, is, contrarv 

 to the views generally held, associated with great plasticity 

 in the other directions. — The classification and nomen- 

 clature of the arable earths according to their mineralogical 

 constitution : H. Lagratu. — On the reddening of the vine 

 leaf : L. Ravaz and L. Roos. .A study has been made 

 from the chemical standpoint of the non-parasitic redden- 

 ing of the leaf of the vine. The results confirm the theories 

 of Bcehm and some other authors on the solution and 

 migration of the carbohydrates in the leaf. — Stcr{g,main- 

 cystis nigra and oxalic acid ; P. G. Charpentier. Oxalic 

 acid is a product of the growth of this mould when culti- 

 vated in Raulin's solution, and is still produced when the 

 tartaric acid of this solution is replaced by sulphuric acid. 

 But if the Raulin's solution is deprived of sugar, and the 

 tartaric acid is the only source of carbon, then oxalic acid 

 is not formed. — On the mending of wounds in cartilage 

 both from the experimental and histological points of view : 

 \ . Cornil and Paul Coudray. — On accommodation and 

 convergence in binocular vision : Leon Pigreon. — The 

 geological structure of the central Sahara : Emile Haug. 



CONTENTS. PAGE 



The Mathematics of Naval Strategy and Tactics. 



By Sir W. H. White, K.C.B., F.R.S -,6i 



The Correspondence of Huygens. By J. L. E. D. . :;62 



Psychiatry jgj 



Our Book Shelf :— 



Osterhout : " Experiments with Plants " 364 



Ostwald : " Conversations on Chemistry." — A. S. . 364 

 Ball: " Mathematical Recreations and Essays '■ . . . 364 

 Letters to the Editor: — 



The Rate of Formation of Radium. — Hon. R. J. 



Strutt, F.R.S 365 



The Effect of Radium on the Strength of Threads.— 

 Hilda P. Martin and Prof. W. B.' Morton . . 365 

 American Research in Asia. (Illustraled.) By Prof. 



Grenville A. J. Cole 366 



Habits of Birds. (Illustrated.'] By R. L 367 



The South African Meeting of the British Association 368 

 Inaugural Address by Prof. G. H. Darwin, M.A.. 

 LL.D., Ph.D., F.R.S., President of the Associa- 

 tion. Part I 36S 



Section A. — Mathematics and Physics. — Opening 

 Address by Prof. A. R. Forsyth, Sc.D., LL.D,', 

 Math. D., F.R.S., President of the Section . . 372 

 Section B. — Chemistry.— Opening Address by G. T. 

 Beilby, President of the Section. {Illustrated.) . 37S 



Notes 3S4 



Our Astronomical Column : — 



The Planet Mars 388 



The Rings of Saturn 3SS 



Declinations of Certain North Polar Stars 3S8 



The Minor Planet Ocllo (475) 3S8 



The Rciyal University Observatory of Vienna . . . . 388 



The State and the Clayworker 3S8 



The Cerebellum : its Relation to Spatial Orientation 

 and Locomotion, lly Sir Victor Horsley, F.R.S. 389 



University and Educational Intelligence 390 



Societies and Academies 391 



