6o8 



NA TURE 



October 19, 189^ 



Paris. 



Academy of Sciences, October 9. — M. Lcewy in the 

 chair. — On the theory of pyro-electricity and piezo-electricity, 

 by Lord Kelvin. — On a class of new transcendentals, by M. 

 Emile Picard. — Theorem on triple orthogonal systems, by M. 

 Lucien Levy. — Circles or spheres derived from a plane or solid 

 envelope of any class, by M. Paul Serret. — On the aperture 

 fringes, in the experiment with parallel gratings, by M. 

 Georges Meslin. These fringes are independent of the 

 form, the size, and the orientation of the slit ; they do not 

 require a particular position of the screen or the slit, and the use 

 of a lens is not indispensable. Their essential characteristic is 

 that of exhiiiiting alternate colorations, which are sensibly com- 

 plementary. In other respects they present the same aspect as 

 those produced by one slit illuminating one grating. But the 

 black fringes, which are very fine in the first case, are less 

 sharply defined ; the second phenomenon does not reproduce 

 the delicate portions of the first, but shows only those bands 

 which have a certain breadth. If the periods of the gratings 

 are identical, the bands are sharply defined. If the illuminat- 

 ing grating has a number of slits per mm. equal to half that of 

 the second, the colorations ate the same, but less brilliant. 

 On reversing the positions, the fringes become achromatic, 

 owing to the superposition of the red and green bands 

 of the two systems. — On the relation between the precipita- 

 tion of chlorides by hydrochloric acid and the lowering 

 of the boiling point, by M. R. Engel. To precipitate 

 one molecule of a chloride from its saturated solution at 0° re- 

 quires in the case of monovalent chlorides, one molecule of 

 HCl, and in the case of divalent chlorides, two molecules. 

 This is now proved also to hold good for temperatures other 

 than o", and for double chlorides, like that of copper and am- 

 monium, containing lour atoms of chlorine and requiring four 

 molecules of HCl. The molecular depression of the freezing 

 point of solutions of the various chlorides was also investigated 

 in its relation to the concentration. It was found that for the 

 monovalent chlorides the molecular depression remains sensibly 

 the same, varying between 35 and 40, but tends to reach twice 

 that value for divalent, and four times that value for tetravalent 

 chlorides. Hence at the freezing point of the saturated solution 

 of alkaline chlorides, bromides, and iodides, there must be a 

 relation between the atomic weights of the constituents of the 

 molecule and the solubility. — On the variations of glycogeny in 

 anthrax infection, by M. H. Roger. The glycogenic function 

 remains intact during the first stages of anthrax infection. The 

 amount of sugar contained in the blood is normal or slightly 

 diminished. At the end of the disease, the hepatic glycogen 

 rapidly disappears and a considerable hyperglycemia is pro- 

 duced. — Researches on the extension of the blastoderm and 

 the orientation of the embryo in the ova of the Teleostea, 

 by MM. R. Koehler and E. Bataillon. — On the locali- 

 sation of the active principle in the Capparideas, by M. 

 Leon Guignard. The existence of special ferment cells is 

 general in the Capparideje. By their morphological cha- 

 racteristics in the root and the stem they resemble those 

 found in the corresponding organs of the Cruciferte. In 

 the leaf and especially the flower of the caper-tree their 

 grouping is peculiar. AH the reactions of their contents are 

 those of myrosine. In the capers they are most numerous, and 

 the glucoside is most abundant. The grains of all Capparideoe. 

 however, are relatively poor in ferment and in glucoside, and of 

 their two constituents the embryo alone contains the ferment. — 

 Sexual reproduction of the Ustilagineee, by M. P. A. Dangeard. 

 — On plane-tree honey, by M. Edm. Jandrier. During dry 

 summers an exudation of varying consistence and aspect may 

 be found on certain planes {Plala?ius OHentalis). It is some- 

 times dry and bright, sometimes pasty and yellowish, and 

 contains, besides a small quantity of reducing sugar, probably 

 glucose, about 80 or 90 per cent, of mannite, which may be 

 extracted with the greatest ease by means of boiling alcohol 

 and crystallisation. — Observation of an Aurora Borealis, by 

 M. le due Nicolas de Leuchtenberg. This was observed from 

 the camp at Krasnoe Selo in the middle of July, about 

 loh. 30m. p.m. Its apex was situated very near the zenith, 

 and seemed based upon a cluster of light vapours from which 

 regular and regularly spaced bands proceeded, passing from 

 white to a delicate pink and green, with a vibration resembling 

 that exhibited by rarefied gases in Geissler tubes. It was seen 

 to last about a quarter of an hour. 



NO. 1251, VOL. 48I 



BOOKS, PAMPHLETS, and SERIALS RECEIVED. 



Books. — Solutions of the Examples in the Elements of Statics and 

 Dynamics : S. Soney (Camb. Univ. Press). — An Elementary Treatise on 

 Theoretical Mechanics, Part i, Kinematics: A. Ziwet (Macmillan). — Text- 

 book of Geology : Sir K. Geikie, 3rd edition (Macmillan). — Eskimo Life : 

 F. Nansen, translated by W. Archer (Longmans).— Key to Carroll's 

 Geometry (Burns and Oatcs). — The Shrubs of North-eastern America : 

 C. S. Newhail (Putnam). — Handbook of Public Health and Demography : 

 Dr. E. F. Willoughby (Macmillan). — -An Elementary Treatise on the 

 Geometry of Conies: .A. Mukhopadhyay (Macmillan). — -A Treatise oir 

 Hygiene and Public Health, Vol. 2, edited by Dr. T. Stevenson and S F. 

 Murphy (Churchill). — Vorlesungen iiber Maxwell's Theorie der Elektricitat 

 und des Licht^s ii. Theil : Dr. L. Boltzmann (Leipzig, Barth). — Healthy 

 Hospitals : Sir D. Galton (Oxford. Clarendon Press). — Sporonen als Krank- 

 heitserreger, Erstes Heft: Dr. A. Korotneff (Berlin, Friedliinder). — Zoo- 

 logical Record 1892 {Gurney and Jackson). — Everybody's Letter Writer 

 (Saxon). — The Out-door World : W. Fumeaux (Longmans). 



Pa-mthlets. ^Reports of the Director of the Michigan Mining School for 

 1890-92 (Lansing). — Anleitung zur Krystallberechnung : Dr. B. Hecht 

 (Leipzig, Barth). — Report on the Present State of our Knowledge respecting 

 the General Circulation of the Atmosphere : L. T. de Bort (Stanford). — 

 History of Slavery in Connecticut: Dr. B. C. Steiner (Baltimore). — Mer- 

 chant Venturer's School, Prospectus 1S93-94 (Bristol). — The Interdependence 

 of Abstract Science and Engineering : Dr. W. Anderson (London). 



Serials. — Mind, October (Williams and Norgate). — American Meteoro- 

 logical Journal, October (Ginn).— Boletin del Instituto Geografico Argen- 

 tino, tomo xiv. Cuadermos i to 4 (Buenos Aires). —American Journal of 

 Science, October (fJew Haven). — American Naturalist, September (Phila- 

 delphia). — John Hopkins University, Baltimore, Studies from the Biological 

 Laboratory, Vol. v. No. 4 (Baltimore). — Records of the Geological Survey 

 of India, Vol. xxvi. Part 3 (Calcutta). — Botanische Jahrbiicher, Siebzehnter 

 Band,_3 and 4 Heft (\VilIiams and Norgate). — Kryptogamen-Flora von 

 Schlesien, 3 Band, 2 Hiilfte, i Lief (Williams and Norgate). — Annals of 

 Scottish Natural History, No. 8 (Edinburgh, Douglas). — Agricultural 

 Gazette of N.S.W., August (Sydney). — Palestine Exploration Fund. 

 Quarterly Statement, October (Watt). — Nyt Magazin for Natur viden- 

 skaberne, 34 ke Binds, 2 det Hefte (Christiana). — Proceedings and Trans- 

 actions of the Nova Scotian Institute of Science, Halifax, 2nd series. Vol. 

 i. Part 2 (Halifax, Nova Scotia). 



CONTENTS. PAGE 



British Butterflies. By W. F. Kirby 585 



Cooke on Locomotives. By N. J. Lockyer .... 586 



Weather Prophesying. By W. E. P 587 



Our Book Shelf:— 



Manson : "Geological and Solar Climates: their 



Causes and Variations." 5^^ 



Burch : " A Manual of Electrical Science " . . . . 588 



Letters to the Editor : — 



The Supposed Glaciation of Brazil. — Dr. Alfred R. 



Wallace, F.R.S 589 



Telegony. — M. D. H 590 



The Use of Scientific Terms.— Prof. W. R. Fisher 590 

 Rustless Steel. — H. G. Fourcade 590 



Research Laboratories for Women. By Prof. A. W. 

 Rilcker, F.R.S 590 



The Inner Structure of Snow Crystals. {Illustrated.) 

 By G. Nordenskirild 592 



Biitschli's Artificial Amoebae. By Dr. John Berry 

 Haycraft . . 594 



Finger-prints in the Indian Army. By Francis 

 Galton, F.R.S 595 



Notes 596 



Our Astronomical Column : — 



The Scintillation of Stars 600 



A Universal Telescope Stand 600 



Popular Astronomy 600 



The August Meteors 60 1 



Astronomy of the Fellahin of Palestine 601 



Geographical Notes 601 



The Harveian Oration. By Dr. P. H. Pye-Smith, 



F.R.S 6ci 



The Effect of Water Vapour on Electrical Dis- 

 charges 605 



University and Educational Intelligence 606 



Scientific Serials . 606 



Societies and Academies 607 



Books, Pamphlets, and Serials Received 608 



