6oo 



NA TURE 



[Al'RIL 21, 1892 



Amsterdam. 

 Royal Academy of Sciences, April 2.— Prof, van de 

 Sande Bakbuyzen in the chair. — Mr. Kapteyn communicated 

 the resul> of a discutision of a great part of the photofjraphs 

 taken at the Cape Observatory under the direction of Her 

 Majesty's Astronomer, D. Gill. The diameters of the stars on 

 370 of these photographs, covering an area of nearly 9000 

 square degrees of the sky, have been compared to the visual 

 magnitudes of these stars according to the estimations of Messrs. 

 Gould and Schonfeld. It is shown that for stars of equal visual 

 brightness the actinic effect on the plates has been considerably 

 greater for the stars situated in or near the Milky Way, than for 

 stars situated in considerable galactic latitudes. The different 

 causes that may have co-operated to produce this phenomenon 

 have been carefully consiHered, and the conclusion is arrived at, 

 that neither influences of meteorological causes, nor causes of 

 systematically different sensitivity of the plates, are sufficient to 

 account for it ; and that the systematic errors in the estimations of 

 the visual magnitudes are, in all probability, of secondary import- 

 ance. It seems very probable, therefore, that the principal cause 

 must be sought in peculiarities of the light of the stars themselves. 

 The fact discovered by Mr. Pickering, that the Milky Way 

 must be considered as an aggregation of stars of the first type 

 explains only a small fraction (not o'l mag.) of the differences 

 found. Mr. Kapteyn therefore thinks that w^e are driven to 

 the conclusion that the light of the stars of the first type in the 

 Milky Way is considerably richer in violet rays than the light of 

 stars of the same type in great galactic latitudes. From this would 

 follow, according to the researches of Mr. Pickering, that the same 

 must hold for stars of the other spectral types. In the mean- 

 while direct photometric and photographic experiments seem 

 very desirable, in order to prove the reality of the phenomenon 

 by more direct evidence than is contained in the plates of the 

 Photographic Survey. Such experiments have been already 

 undertaken by the Cape Observatory. — Mr. Hubrecht gave an 

 account of the placentation of certain Lemurs and Insectivora, 

 as a result of his recent excursion in the Indian Archipelago. 

 The placenta of Tarsitts spectrtim is a discoid one, and differs from 

 that of other Lemuroids hitherto known, in which a diffused dis- 

 tribution of villi over the whole surface of the chorion has been 

 observed. In Nycticebus this coating loses its villous character 

 at one pole of the egg in the latest stages of pregnancy. Certain 

 stages of the discoid placenta of Galeopithecus were further 

 described, as was also the double placenta of Tupaja javanica, 

 each placenta having a reniform shape, these being situated right 

 and left of the embryo, which has its ventral surface turned 

 towards the mesometrium. — Mr. Pekelharing reported on his 

 further investigations about the coagulation of the blood. He 

 states that the A. fibrinogen of Wooldridge is the same substance 

 which can be precipitated from the diluted plasma by acetic 

 acid, viz. a nucleo albumin, the zymogen that, by combination 

 with lime, forms fibrin ferment. Wooldridge's tissue-fibrinogen is 

 also a nucleo-albumin from which can be obtained, by treating it 

 with lime-salts, fibrin ferment. In accordance with Dr. Wright, 

 Mr. Pekelharing has found that, in the dog and in the rabbit, an 

 albumose can be split off from the nucleo-albumin, and in this 

 manner the formation of the fibrin ferment can be prevented, or 

 the action of the ferment already formed can be paralyzed. 



DIARY OF SOCIETIES. 



London. 



THURSDA V, April 21 

 LiNNRAN Society, at 8. — On some New Plants from China : W. B. 

 Hemsley, F.R.S.— On the Relation of the Acaridae to the Arachnida : H. 

 M. Bernard. 

 Chemical Society, at 8. 



FRIDA y, April 22. 

 Institution of Civil Engineers, at 7.30. — The Speed and Power of 

 Locomotives ; Edmund L. Hill. 



SATURDAY, April 23. 

 Royal Botanic Society, at 3.45. 



MONDAY. April 25. 

 Aristotelian Society, at 8. — Prof. Wm. James's Treatment of Self: G. 

 Dawes Hicks. 



TUESDAY, April 26 

 Anthropological Institute, at 8.30. — The Social and Religious Ideas 

 of the Chinese, as illustrated in the Ideographic Characters of the 

 Language : Prof R. K. Douglas. — The Mythology and Psychology of 

 the Ancient Egyptians : Joseph Offord, Jun. 

 Royal Statistical Society, at 7.45. — An Inquiry into the Statistics of 

 the Production and Consumption of Milk and Milk Products in Great 

 Britain: R. Henry Rew. 



fNSTiTiTTioN OF CiviL ENGINEERS, at 8. — Electric-Light Measuring In 



struments : James Swinburne. 

 Photographic Society, at 8. 

 Royal Institution, at ^.— The Sculpturing of Britain — its Later Stages: 



Prof T. G. Bonney, F.R.S. 



WEDNESDA Y, April 27. 

 Geological Society, at 8.— Notes on the Geology of the Northern 



Etbai or Eastern Desert of Egypt ; with an Account of the Emerald 



Mines : Ernest A. nFloyer. — The Rise and Fall of La.ke Tanganyika : 



Alex. Carson. (Communicated by R. Kidston.) 

 Kmto\«ological Society, at 7. 

 British Astronomical Association, at 5. 



THURSDAY, April 28. 

 RovAL Society, 314.30. 

 Institution of Electrical Engineers, at 8.— Notes on the Light of the 



Electric Arc : A. P. Trotter. 

 RovAL 'nstitution, at 3. — The Chemistry of Gases: Prof. Dewar, 



F.R.S. 



FRIDAY, April 29. 

 Institution of Civil Engineers, at 7.30. — The Steam-Hammer and its 



Relation to the Hydraulic Foreing- Press : H. H. Vaughan. 

 Royal Institution, at 9.— The Physiology of Dreams: Dr. B. W. 



Richardson, F.R.S. 



SATURDAY, April 30. 

 Royal Institution,- at 3.— J. S. Bach's Chamber Music (with many 



Musical Illustrations): E. Dannreuther. 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Books.— Blowpipe Analysis, 2nd edition: T. Landauer; translated by 

 J. Taylor (Macmillan).— Air Oinprim^ ou Rarefi6 : A. Gouilly (Paris, 

 Gauthier-Villars).— La Distribution de I'Electricite, Installations Isolees : 

 R. V. Picou (Paris, Gauthier-Villars).— Resistance des Mate'riaux : M. 

 Duquesney (Paris, Gauthier-Villars).— Machine a Vapeur : V. Dwelschau- 

 vers-Dery (Paris, Gauthier-Villars).— Elements of Materia Medica and 

 Therapeutics : C. E. A. Sample (Longmans).— Fruit Culture: J. Cheal 

 (Bell). — My Water-cure : S. Kneipp (Grevel).— Color-vision : E. Hunt 

 (Si-"pkin). 



Pamphlet.— On the Physics of Media: J. J. Waterston (Kegan Paul). 



Serials.— The Asclepiad, No. 33, vol. ix. (Longmans).— Geological 

 Magazine, April (K. Paul). Journal of the Royal Agricultural Society, 

 3rd series, vol. iii. Part i (Murray).— Himmel und Erde, April (Berlin, 

 Paetel).— The Annals of Scottish Natural History, N >. 2 (Edinburgh, 

 I'oiiglas).- Journal of the Institution of Electrical Engineers, No. 96. 

 vol. xxi. (Spon)— The Eagle, March (Cambridge, Johnson).— Journal of 

 Anatomy and Physiology, vol. xxvi. Part 3 (Williams and Norgate).— Mmd, 

 April (Williams and Norgate).— Massachusetts Institute of Technology, 

 Boston, Annual Catalogue, 1891-92 (Boston). — lournal of the Royal 

 Statistical Society, March (Stanford).— Journal of the Chemical Society, 

 April (Gurnev and Jackson). — Bulletin de TAcadimie Imp^riale des Sciences 

 de St. Petersbr.urg, ncuvelle serie, ii., xxxiv., feuilles 34-41.— The Engineer- 

 ing Magazine, April (New York). 



PAGE 



• 577 



CONTENTS. 



The Yahgan 



Quantitative Analysis. By J. W. R 578 



Astronomy 579 



Our Book Shelf: — 



Cheal: " Practical Fruit Culture" 579 



Landauer: " Blowpipe Analysis " 580 



Letters to the Editor : — 



Prehistory of Egypt —W. M. Flinders Petrie . 580 

 Aphanapteryx in the New Zealand Region. — Prof. 



Henry O. Forbes . . . 581 



Pigments of Lepidoptera.—F. Gowland Hopkins 581 

 C.G.S. System of Units.— O. H. Tittmann ; Prof. 



J. D. Everett, F.R.S. 



Influenza in America.— Prof. Edward S. Holden 

 Dust Counting on Ben Nevis. By Angus Rankin 

 Abstract of Mr. A. Ricco's Account of the Sub- 

 marine Eruption North-west of Panielleria, 

 O tober 1891. {Illustrated.) By G. W. Butler . 



Giraffes 



Notes 



Our Astronomical Column : 



Astronomy at the Paris Academy, April II . . . . 



Solar Heat ... 



Periodic Variations in Latitude 



Recent Advances in Physical Chemistry, By Prof. 



W. Ostwald 



The General Circulation of the Atmosphere. By 



Dr. J. M. Pernter 



Relation of V- Itaic Electromotive Force to Mole- 

 cular Velocity. By Dr. G. Gore, F.R.S. . . 



Scientific Serials 59^ 



Societies and Academies 597 



Diary of Societies 



) Books, Pamphlets, and Serials Received . 



582 

 582 



584 

 58S 

 58s 



589 



589 

 589 



590 



593 



596 



600 

 6co 



NO. II 73, VOL. 45] 



