No. [NEW SERIES.] MARCH, 1907. Entered at Stationers Hall. SIXPENCE- NET. SEP 9.1 168 n Extraordinary Reptile. CONTENTS. Halley's Comet. ^snYor S 1 The Observation of Meteors and Meteoric Showers. Features of the Earth and Moon. Practical Aerodynamics and The Theory of Aeroplanes. The Face of the Sky for March. NOTES. — Astronomical, Botanical, Chemical, Geological, Ornithological, Physical, Zoological. PHOTOGRAPHY. MICROSCOPY. REVIEWS. &c, &c. CATALOGUE (section 1- MIGROSGOPES and ACCESSORY APPARATUS. READY EARLY MARCH. Entirely rewritten and enlarged. C. BAKER, 244. HIGH HOLBORN, LONDON. FOR — X-RAY, &c, APPARATUS, See the Advertisement of the ACTUAL MANUFACTURERS, HARRY W. COX, Ltd., On Back Cover. 'TIS TOLD BY THE TASTE Judges of good cocoa have learned to distinguish "FRY'S PURE CONCENTRATED" from all others by reason of its unequalled flavour, aroma 3 and digestibility, a few sips being suthcient toS proclaim its superiority. PURE CONCENTRATED Hioeocu THE ORIGINAL FIRM ESTABLISHED 1728 There's Health in every Cup. NEWTON 4 CO.'S " DEMONSTRATOR'S LANTERN. FOR LIMELIGHT OR ELECTRIC. With Prism for Erecting, and for Vertical Projection. JAS. J. KICKS, 'holesale Maker of Meteorological and other Scientific Instruments. The most simple and efficient Single Lantern yet constructed for general scientific work. .\e.r E.lition of Urn- i Catalog Sixpence. 3, FLEET ST., LONDON. Opticians bv appointment to H.M. thfl King, H.R.H. tha Prince of Wales, and tlie tiovt- DARTON'S NEW DIAL BAROGRAPH, WITH VERTICAL SCALE AND INDEX HAND . . . E»«*lo» «:». Smaller size £4. May be obtained through any Optician or of the SOLE MAKERS, F. DARTON & CO., CL,S;V;,„s, 142, ST. JOHN STREET, LONDON, E.C. ACt'fM. yf.iKF.US Of OH M .,-u\$. IlLi. l>ottlgn ShtiOt o( all forms of Hirornvtcit Iroe. WILSON'S PATENT RADIO-INTEGRATOR Designed by Dr.W. B. Wilson, F.R.S.. to record the total amount of Solar Radiationdaily received by the ground. and full particulars on appli.a 8, 9, & 10, HATTON GARDEN. LONDON. THE NEW NATURALISTS' CAMERA. PATENT OAkkMCrCM L'.» :■ K lot Ordinary or Telonhoto. LenMfl ILLUSTRATED PROSPECTUS FREE. J. H. DALLMEYER, Ltd., optical manufactory, 25, NEWMAN ST., LONDON, W. Mnktis o! t]ir 0, , l>rvt, ,1 Dallmoyet 1 euses. This Journal may be obtained (in any case to order) at all Bookstalls and Newsagents. OFFICES i-27, CHANCERY LANE, LONDON, W.C KNOWLEDGE SCIENTIFIC NEWS. [March, 1907. RADIUM ON HIRE! Activity 1,800,000.) Lectures ®. Demonstrations Arranged on Radium. X-Rays. or Wireless Telegraphy. Town or Country. RADIUM MICROSCOPES, Complete with Radium, 2/6 and 7/6 each. These are SELF LUMINOUS in the dark, showing splendid Scintillations. Pitchblende Scintilloscopes Extra Screens for Testing Minerals 7,6 each. 1/6 each. F. HARRISON GLEW (sR,?«?%™SXrst), 156, Clapbam Kd. London, S.W. Telephones: 1787 Hop and 3117 Hop. BIRKBECK COLLEGE, BREAMS BUILDINGS, CHANCERY LANE. E.C. FACULTY OF SCIENCE. DAY AND EVENING COURSES, under recognlr.od Teachers of the University of London. I Alex. McKknzik, Ph.D., D.Sc, Chemistry - MA. I II. Which, Ph.D., B.A., B.Sc. I Albert Griffiths, D.Sc. -I). Own. B.A., B.Sc. (B. W. Clack, B.Sc. I E. H. Smart, M.A. IC.V. Coates, M.A. Botany V. H. Blackman, M.A. Zoology H. W. Unthank, B.A., B.Sc Goology & Mineralogy J. VV. Evans, D.Sc. Assaying, Metallurgy & Mining .. Geo. Patcnin, A.R.S.M. RESEARCH in Chemistry and Physics in wall-equipped laboratories. French, German, Spanish, and Italian Classes. EVENING CLASSES in Biology, Physiology, Practical Geometry, Building and Machine Construction, Theoretical Mechanics, Applied Mechanics and Mechanism, Land and Quantity Surveying. Calendar 3 limelight, !-*%■■* I Cr^l^«J ACETYLENE, OR ELECTRIC LIGHT. LANTERN SLIDES OF SCIENTIFIC SUBJECTS, and of places In all parts of the world. CATALOQUES (Parts V. & VI.) GRATIS. SPECIAL SHOWROOM at 406, STRAND, with large Number of Slides Illumi- nated by Electric Light for easy selection. J¥¥ ^TlPTJir A T?Tl Optician to the British • JT» \J X ML* WW jt\t\.LJ t &, Foreign Governments, 406, STRAND; 457. WEST STRAND, LONDON. k WATKINS and DONCASTER, NATURALISTS And Manufacturer* of Cabinets and Apparatus ENTOMOLOGY, BIROS' EOOS AND SKINS, AND ALL BRANCHES OF NATURAL HISTORY. SPECIAL SHOW-ROOM FOR CABINETS. N.B. — For Excellence and Superiority of CabiruU and Apparatus, references are permitted to dUCin. guishid Patron*, Museums, Colleges, itc. A LARGE STOCK OF INSECTS AND BIROS' EGQS AND SKINS. SPECIALITY.— Objects for Nature Study, Drawing Classes, &c. Birds, Mammals, etc., Preserved and Mounted by First-class Workmen true to Nature. ,__ All Books and Publication! on Natural •^^ History supplied. 36, STRAND, LONDON, W.C. (Five doors from Charing Cress.) f»r Catalogue (102 pp.) post free. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. iii. MOW RELADY, THE SCIENCE YEAR BOOK DIARY, DIRECTORY, BIOGRAPHY, & SCIENTIFIC SUMMARY FOR t 90 V . FRONTISPIECE.- Portrait of Lord Rayleigh. ASTRONOMY. — The Calendar, Monthly Ephemeris, Tables for Latitude, Longitude, &c, Notes and Tables of Solar System, Paths of the Planets (with Charts), the Moon, Eclipses, Comets, Jupiter's Satellites, the Stars, Maps of the Heavens, &c. THE EARTH AND ITS INHABITANTS.— Notes and Charts on Geology, Magnetism, Meteorology (Average Temperature, Rainfall, &c), Geographical Exploration, Natural History, Populations, Statistics, &c. PHYSICAL AND CHEMICAL NOTES.-Air and Water, Light, Sound, Heat, Specific Gravities, Spectra, Chemical Elements, &c. METROLOGY. — Time, Trigonometrical Tables, Weights and Measures, Electrical Measure- ments, Money, &c. PROGRESS OF SCIENCE IN 1906. DIRECTORY. — Scientific Periodicals, Public Institutions, Universities and Staffs, Scientific and Learned Societies, Prizes and Awards, &c. BIOGRAPHIES of over 500 of the Principal Workers in Science. GLOSSARY of recently-introduced Scientific Terms. DIARY.— One Page to each Day, Times of Sunrise and Sunset, High Water, Moon, Meteorological Averages, Astronomical Events, &c. Engagement Diary and Calendar. Letters received and despatched, Memoranda, Cash Accounts, INDEX Postal Information, &c, &c. Nearly 600 Pages, Large Octavo, handsomely bound in Cloth, Gold Lettering, with Changeable Monthly Calendar in Cover, PRICE B5/ NET ^ POSTAGE:— Inland, 5&. Abroad, lid. {including special packing.) *^2 ABRIDGED EDITION, consisting of the whole of the above contents, but without the Diary ■Inland, 3d. Abroad, 6d. [including special packing.) SAME BINDING, PRICE CB/- NET. j P°STAGE SOME EXTRACTS FROM OPINIONS OF THE PRESS ON THE 1906 ISSUE. " Every care appears to have been taken to make the volume serviceable to men of science and others interested in natural knowledge. . . . The Year Book is thus a convenient and helpful companion for the study, laboratory, or observatory." — Nature. " A very excellent and thoroughly up-to-date annual." — English Mechanic. " The additions and improvements made in the current issue of this well-known scientific diary make it, if possible, even more indispensable than ever to naturalists and scientific men." — The Naturalist. " The whole production is unique, and its general get-up is beyond praise." — Eltcttieal Re " Of the stream of year-books .... very few — if indeed any — can surpass in point of use- fulness and excellence of appearance the volume before us." — The Electrical Engineer. " It is beautifully produced, on good paper, and full of information in all branches of scientific work, especially astronomy. It is one of the best five shillings' worths in the market." — Eltch " The whole is admirably arranged, and the book should have the widest circulation, for it appeals to the ordinary man as well as the student." — Athcnu-um. " One book of reference that is really readable is the ' Science Year Book.' " — Daily Graphic. " It contains an enormous amount of information in the way of statistics, and is altogether very cleverly arranged." —The Sphere. Publishing Office - 27, Chancery Lane, London OR THROUGH ANY BOOKSELLER. IV. KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. SYMONS'S METEOROLOGICAL MAGAZINE. Edited by HUGH ROBERT HILL, D.Bo. Aji Illustrated Journal of Meteorology imblisheil on the 16th of ercrj month, riimitological and Rainfall Tables of tho British Inlands and the llrilish Empire are published monthly, together with tho latest news of the progress of Meteorological Science in all countries, Correspondence, and Hoviewsof Books. k specimen number will be sent free on application to the Editor at 63, Camden Square, London, N.W. Subteription 6«. per annum, post free. Single number, price id. EDWARD STANFORD, la, 13, and 14, Long Acre. W.C. THE SCIENCE YEAR BOOK for 1 907. See Advertisement on preceding page. W. WESLEY & SON, 28. ESSEX ST.. LONDON. W.C, Have recently published NORMAN, A., and T. SCOTT, THE CRUSTACEA OF DEVON AND CORNWALL, 24 plates, 8vo, cloth, 1906, £1 4s. net. This work records with notes 808 species (120 podophthalma, 13 sympoda, 6H isopoda. 144 amphipotla. 30 branchiopbda, i<>; ostracoda, 29a copepoda, cirripedia'. The plates illustrate new or little known species of isopoda, amphipoda, and copepoda. HAGENBACH, A., and H. KONEN, ATLAS OF EMISSION SPECTRA OF MOST OF THE ELEMENTS, prepared from photographs with explanatory Text. Authorized English edition by A. King, 28 plates, 4to, ■905. /i 7s- ne'- The volume contains no fewer than 280 photogravures exhibiting the spectra of 68 out of a list of 79 elements. With the exception of fluorine, the 11 elements omitted all belong to the class described as "extremely rart"; so that we have before us the most comprehensive survey of spectra ever published. BOTANICAL CATALOGUE in two parts, Price 6d. each. JUST PUBLISHED. The Scientific Papers of J. WlLLARD GIBBS. Ph.D., LL.D., Formerly Professor of Mathematical Physics In Yale University. Willi Photogravure 1 'ortrait. 2 Vols, royal .Svo (sold separately) Vol. I. THERMODYNAMICS. 24s. net. Vol. II. DYNAMICS, VECTOR ANALYSIS and MUL- TIPLE ALOKBRA. ELECTRO-MAGNETIC THEORY OF LIGHT, &c. 18s. net. PROSPECTUS BENT (>N APPLICATION. LONGMANS, GREEN & CO., 39, PATERNOSTER ROW, LONDON, E.C. their lives and useful labours are being described in a work appearing in num- bers, 1/- each. Nos. 17 & 18-VITAL CHEMISTRY : General. No. 10— VITAL CHEMISTRY: General (.mil. ,, ,, ,, ,, Acids (commenced). ACETIC ACID will appear shortly. Subscription price 1/-. For Prospectuses and Particulars apply to RAMSAY, 15, Lawn Crescent, Kew Gardens, Surrey. BACTERIA ; BOOKS. Publishers' Remainders in all branches of Literature, including Science. H. J. GLMSHER'S March Catalogue Now Ready. Post Free. BOOKS AT BARGAIN PRICES. H. J. GLAISHER, REMAINDER AND DISCOUNT BOOKSELLER, 57, WIGMORE STREET, LONDON. W. »«BI THE DAILY NEWS I Head Office: BOUVERIE STREET, LONDON. E.C. The Largest Halfpenny Morning Paper in England. "THE DAILY NEWS" is a marvel of modern newspaper production. Buy a copy to- 8 morrow morning, and take it home at night. You will be astonished at the variety of its contents, and your family will be delighted with it. GUARANTEED CIRCULATION EXCEEDS 200,000 COPIES PER DAY. SOLD BY ALL NEWSAGENTS. Or sent post free one week, 6d. ; 4 weeks, 2/- ; one quarter, 6/6. WEEKLY EDITION. EVERY FRIDAY. PRICE 2d. Or with one Supp'm't (Literary, Engineering or Financ'l) 3d. Contains a careful Epitome of the Events of Interest during the Week, together with the Most Important Leaders and Special Articles from "The Times" in extenso. Parliament and Politics. Colonial and Foreign News. Naval and Military Matters. Trade, Money and Stocks. Ecclesiastical and Social Notes. Reviews of Books. Law and Police. Home and Domestic Events. Correspondence. Chess by Special Expert. News interesting to every class of reader ; and a Serial Work of Fiction. Special Supplements are Published for Australasia and India, for Canada and U.S., and for Sth. Africa. TERMS OF SUBSCRIPTION. Inland ,, with Literary Supp'm't Foreign ,, with Supp'm't (Literary, Engineering, or Financial) 3 Months. as. od. . 3s. iod. . 3S. 3d- • 4S. loAd. . 12 Months. iis. od. 15s. 4<1- 13s. od. 19s. od. Address -.-THE PUBLISHER, PRINTING HOUSE SO., LONDON. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. v. v CONTENTS, v An Extraordinary Reptile. By R. Lydekker {with illus- tration) . . . . . . . . . . . . . . . . 49 The Observation of Meteors and Meteoric Showers. By W. F. Denning 51 Lord Kelvin on Earthquakes .. '.. 52 Features of the Earth and Moon — Craterlets and Canals [with illustrations) .. . . . . . . . . 5 j Halley s Comet. By F W. Henkel, B.A . F.R.A.S., diagram) . . . . . . . . . . . . 57 Practical Aerodynamics and The Theory of Aero- planes—II. Head Resistance to a Body Moving Through the Air. By Major B. Baden-Powell .. 59 Correspondence .. .. .. .. .. .. .. 60 Physics and Biology. By John Butler Burke, M.A. (Carab. and Dubl.). 61 Photography : Pure and Applied. By Chapman Jones, F.I.C., F.C.S., &c 63 Notes. — Astronomical. By Charles P. Bctler, A R.C.Sc. (Lond.), F.R.P.S Botanical. By G. Massee Chemical. By C Ainsworth Mitchell, B.A (Oxon), F.I.C Geological. By Edward A. Martin, F.G.S. Ornithological. By W. P. Pycraft, A.L.S., F.Z.S , M.B.O.U., &c Physical. By Alfred W. Porter, B.Sc. Zoological. By R. Lydekker Reviews of Books Microscopy. Conducted by F. Shillington Scales, B.A , P.R.M.S. (with illustrations) The Face of the Sky for March. By W. Shackleton, F.RA.S. 72 64 64 65 66 66 67 67 68 *• NOTICES, v EDITORIAL communications should be addressed to the Editors, who are not responsible for the loss of MS., &c, submitted. Latter must be accompanied by stamps for return if rejected. BUSINESS letters to the Manager. ADVERTISEMENT matters to the Advertisement Manager. SUBSCRIPTION.— Six issues, 4/- ; Twelve issues, 7/6 ; Special rate for S years, 25/-; post free throughout the world. POSTAGE. — On single copies 2d. each. Offices - - 27. CHANCERY LANE. LONDON, W.C. BOUND VOLUMES.— The Yearly cloth bound Volume of "Knowledge" for 1905, 8/6 net; of "Illustrated Scientific News," 1902-3, 15/- ; post free within U.K. BINDING CASES in blue cloth, gilt design and lettering, 1/6 each; by post 1/9. Readers' parts bound 2/9 per vol. inclusive. REMITTANCES should be made payable to the Manager. LANTERN SLIDES of many of the Plates may be obtained from Messrs. Newton & Co., 3, Fleet Street, London. SECOND-HAND BOOKS. JOHN WHELDON & CO., 38, GREAT QUEEN ST., KINGSWAY, LONDON, can supply most Books in the various branches of SCIENCE AND NATURAL HISTORY, in good condition at moderate prices. STATE WANTS. OR CATALOGUE SENT POST FREE. Scientific & Educational Books NEW AND SECOND-HAND. LARGEST STOCK IN LONDON OF- SECOND-HAND SCHOOL, MATHEMATICAL, MECHANICAL, BOTANICAL, NATURAL HISTORY, ELEMENTARY & ADVANCED SCIENTIFIC BOOKS Of ALL KINDS at about HALF PUBLISHED PRICE. Classical, Theological, and Foreign Books KEYS AND TRANSLATIONS. BOOKS FOR ALL EXAMS. — J. POOLE & CO. IESTD- 1854- 104, CHARING CROSS ROAD, LONDON, W.C. Enquiries by Post receive immediate uttentio GREAT LITERARY FIND !) A firm who can supply cheaper, cleaner copies of any procurable bo:ks or journals than any oiher firm in the trade, and twice as quickly. Write to them. Their address is : E. GEORGE <& SONS. 151. WHITECHAPEL ROAD, LONDON, Wholesale. Retail, and Export Booksellers, ompltte bound set of A ENGLAND. Ktwicleti'je." BROWNING'S McGLEAN'S STAR SPECTROSCOPE, Tor use with a 3-inch or larger Telescope. For Astronomical Work, £2 : 1 O : O. With Slit Adaptor for Chemical and Astronomical Work (in Morocco Case), £3 : 7 : 6. Double Nose-piece for carrying above Spectroscope, and an Eye-piece, or two Eye-pieces, of different powers, £1 : 1 5 : O. HOW TO WORK WITH THE SPECTROSCOPE. A Manual ol Practical Manipulation with 5 J] kinds with ind Diagrams, by JOHN BROWNING, F.R.A.S.. F.R.M.S., 4c, 4c Price Sixpence. Post Free Sevenpence. Illustrated Catalog - oscopts and Sptctronutirs post fret. JOHN BROWNING, Manufacturing Optician, .ESTAB. 1765) 78, STRAND, LONDON. VI. KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. MESSRS. BjLL^JNNOUNCEMENTS. New Work by Sir OLIVER LODGE ELECTRONS ; or, the Nature and Properties of Negative Electricity. Bj Sir Oliver Lodge, D.Sc. (Lond.), Hon D.Sc. (Oxon), LL.D (St. Andrew's, Glasgow and Aberdeen), F.R.S., Vice-President of the Institution of Electrical Engineers, and I'rincipal of the University of Birmingham Demy Hvo. 6s. net. "The subject matter is of die highest interest, and is brought before the reader ina very convincing manner. . . . His exposition is so direct that the ol Li tuaent cm hardly rail to see the force of his reasoning, nr to accept his conclusions."— Kltrtrical Engineer. I >om v Svo. 7s. 6cl. net. INTRODUCTION TO GENERAL INORGANIC CHEMISTRY. By Ai r\ indef Smith. B Sc. (Edin.), Ph.D. (Munich), F.R S.E., Professor of Chemistry and Director of General and I'hysical Chemistry in the University of Chicago. litter, D.Sc., Ph.D.. F.R.S., Professor of Chemistry in University College, Dundee, s.iys : — " I have been favourably impressed with I>r. Alex. Smith's ■ Inorganic Chemistry,' and mean to use it in my classes. In my opinion it is infinitely superior to any book of similar size and run-pose at present available In English, and only needs to be known n order to have a wide circulation." Sma'l ato., with over loo Illustrations. 15s. net. THE GEM-CUTTER'S CRAFT. By Leopold Claremont, author of " A Tabular Arrangement of the Distinguishing Characteristics and Localities of Precious Stones," in the Mining Journal, " The history of the gem from its rough state to its cut and polished final appear- ance is given with remarkable clearness in this work by a cutter of jewels. Mr. Claremont . . . develops his story of 'cleavage,' 'striae,' •dia- phaneity,1 ' lustre,' and ' colour ' in so agreeable a manner that those entirely outside the influence of Hatton Garden will hod his volume at once extremely interesting and informing." — Academy. Semi for detailed Prospectuses of these boohs, mentioning " Knowledge," to GEORGE BELL & SONS, York House, Portugal Street, W.C. MACMILLAN'S NEW BOOKS. FOURTH EDITION. JUST I'UISI.ISHED. INTRODUCTION CHEMISTRY. TO PHYSICAL By Professor JAMES WALKER, Hvo. ios. net. D.Sc, Ph.D., P.R.S. SECOND AND REVISED EDITION OF VOL. II. HANDBOOK OF METALLURGY. By Dr. CARL SCHNABEL, Professor of Metallurgy. Translated by Professor H. Louts, M.A., A.K S.M., F.I C, die. Illustrated. Second Edition. Vol. II. — Zinc, Cadmium, Mercury, Bismuth, Tin, Antimony, Arsenic, Nickel, Cobalt, Platinum, Aluminium. 2is. net. *.* Previously published, Vol. I. Lead, Silver, Gold. 25s. net. Second Edition. — Copper, THE PRINCIPLES AND PRACTICE OF COAL MINING. By JAMES TONGE, M.I M.E , F G.S. With 203 Illustra- tions. Crown 8vo. 5s. net. MINING ENGINEERING.— "This may be considered to be one of the best of Ihe elementary works on coal mining." EXPERIMENTAL ZOOLOGY. By THOMAS HUNT MORGAN. Professor of Experimental Zoology, Columbia University. 8vo. 12s. net. PHOTOGRAPHY FOR STUDENTS OF PHYSICS AND CHEMISTRY. By Professor LOUIS DERR, M.A., SB Illustrated. Crown 8vo. 6s. net. MACMILLAN & CO., LTD., LONDON. GARL ZEISS, JENA. BRANCHES- LONDON: 29, Margaret St., Regent St., W Berlin. Frankfort O/M. Hamburg. Vienna. St. Petersburg. MICROSCOPES Suitable for every class of Scientific and Technical Research. Photo-Micro- graphic AND Projection Apparatus Illustrated Catalogue j, "Jl/A" \Post Free on ♦ ' application. THE MICROSCOPE AND HOW TO USE IT. A Handbook for Beginners, revised and enlarged, with Chapter on Marine Aquarium. By T. CHARTERS WHITE, M.R.C.S., L.D.S., F.R.M.S., late President of the Quekett Microscopical Club. Illustrated with Photo-Micrographs by the Author, and Chapter on Staining of Bacteria by Maurice Amsler, M.B., B.S.Lond. 3s.net. STUDIES IN MICROPETROGRAPHY. Imperial 8vo, with Full-Page Plates in Natural Colours, Key Plates, Explanatory Text and 48 Microscopical Preparations. BEAUTIFULLY COLOURED PLATES. Twelve Monthly Parts, post free to Subscribers only, £4 4 O net. Subscribers who desire to pay their subscriptions by instal- ments, MONTHLY orQUARTERLY, may do so by paying Seven Shillings monthly or One Guinea quarterly in advance. SUBSCRIBERS ORDER FORM WILL BE SENT ON REQUEST, POST FREE. ROBERT SUTTON, PUBLISHER, 43, The Exchange, Southwark, London, S.E. 49 Knowledge & 5cientif ic News A MONTHLY JOURNAL OF SCIENCE. Conducted by MAJOR B. BADEN-POWELL, F.R.A.S., and E. S. GREW, M.A. Vol. IV. No. 3. [new series.] MARCH, 1907. LStationers' Hall .] SIXPENCE NET. CONTENTS.-See page V. An Extraordinary Reptile. By R. Lydekker. Thanks to the authorities of the United States National Museum at Washington, the British public will shortly have the opportunity of seeing, in the Natural History Museum at South Kensington, a restored model of the skeleton of what may well be termed the most extra- ordinary representative of that wonderful group of extinct land reptiles, the Dinosauria. It is not that the Triceratops (as the creature was appropriately named by the late Professor O. C. Marsh, of Vale College) is remarkable on account of its vast bodily size, for in this respect it is not in the running with the giant Diplodocus, whose skeleton was set up a few years ago in the reptile gallery of the museum. Neither does it lay claim to admiration and astonishment on account of walking on its hind legs with its head raised sixteen feet high in the air like its cousin the Iguanodon. On the contrary, Triceratops, so far as bodily size and gait are concerned, has no claim to special distinction, its total length falling just short of a score of feet, while it walked on all fours very much in the fashion of an un- usually long-limbed crocodile. What, however, it lacks in these respects, the three- horned dinosaur, as it may be designated in the vernacu- lar, more than makes up for in the extraordinary con- formation and huge size of its skull. It enjoys, in fact, the distinction of having, both absolutely and relatively, the largest head of any known land animal either living or extinct, and to find a parallel in this respect we must look to the members of the whale tribe, in some of which the relative size of the head is, however, still greater. The horned dinosaurs, of which those commonly designated Ceratops and Triceratops are the best known, were described by Professor Marsh in a series of papers published in the American 1 ournal of Science between 1888 and 1894, inclusive. Their remains oc- cur in the upper Cretaceous beds along the eastern flanks of the Rocky Mountains for a distance of about eight hundred miles, but are more abundant than else- where in Wyoming, and more especially Converse County, where the original of the skeleton forming the subject of the present article was discovered. As an indication of the abundance of these remains in the district in question, it may be mentioned that some years ago a single investigator collected bones refer- able to no less than forty distinct individuals. The Ceratops beds, as they are called, are of fresh-water, or brackish, origin, but rest in some places on marine strata. As they occur some distance below the top- most Cretaceous, their age may be approximately corre- lated with the highest beds of our chalks, so that the horned dinosaurs lived at a much later epoch than the majority of the giant herbivorous dinosaurs, which flourished during the Oolitic and Wealden epochs. By some palaeontologists it has been considered probable that the horned dinosaurs of North America were re- presented by allied types in the upper Cretaceous of Continental Europe, but by others the correctness of this identification is disputed, and the group is regarded as peculiar to America. The skeleton, of which the model sent to this country is a replica, forms one of the most striking objects in the court devoted to vertebrate palaeontology in the museum at Washington, and is the first of itskind that has hitherto been mounted. When discovered, it was far from complete, and it accordingly became necessary to restore the missing bones. So far as possible these missing parts were supplied by selecting- bones from other skeletons of the same approximate size, but when this proved impracticable, as was the case in a few instances, the bones required were modelled in plaster. The skeleton is, therefore, confessedly in some degree a " fake," although the restoration is believed to be practically true to nature. It need scarcely be added that, except on sentimental grounds, the model is in every way as good as the original, although there are doubtless persons who, when they learn this, will ex- claim : " Oh, but it isn't real," and will thereupon cease to take any further interest in the specimen. As mounted, the skeleton measures 19 feet S inches from the front of the curious, toothless beak to the tip of the tail; while at the loins it stands S feet 2 inches. In addition to the skull, which is 6 feet long, or nearly one-third the total length, the most noteworthy features of the skeleton are its great relative height at the loins, the extremely short and deep body (shaped more like that of a mammal than that of a crocodile), the tall and massive limbs, and the curious turtle-like flexure of the fore-feet. Unfortunately, it was found impossible to determine the exact proportions of the front horn in this particular species, so that it was deemed necessar) to omit in the restoration this very characteristic feature, upon which the generic name Triceratops is in part based. In addition to its great absolute and relative the skull is specially characterised by the pi. three horns, one in front ami two behind; the hind pair being strikingly like the horn-cores of a gigantic r>X. Indeed, so ox-like arc these horns that a pair was actually described as indicating a Cretaceous bison. Equally peculiar is the presence of a cutting I formed by a separate bone in each jaw. More striking still is the presence of a great hon\ curtain or frill (like the flange of a fireman's helmet) overhanging the neck, and thus rendering the relative length of the skull greater in respeel to the rest of the skeleton than it really is. Both the horns and the curtain are con- sidered by Professor Marsh to have been covered in life with a thick layer of horn. 5° KNOWLEDGE & SCIENTIFIC NEWS. [Makcii, 1907 Despite the enormous size of the skull, which forms a long triangle in shape, the brain was ol the small size of dinosaurs in general. Whether this implies slow and sluggish habits is not easy to decide. 'J he powerful armature of the skull is, however, suggestive of activity both in attack and del. nee, it being difficult to imagine that such structures were not developed for special purposes. That Triceratops was an herbivorous reptile is evi- dent from the Structure of its teeth, which differ, how- ever, from those of more ordinary dinosaurs in being implanted in the jaws by means of two distinct roots, therein' foreshadowing the mammalian type, although, ol course, there is no direct relationship between this group of reptiles and mammals. By Professor Marsh That the heavy armature ol the head in the Tricera- tops and its allies was developed for purposes of at- tack and defence seems, as already mentioned, almost a certainty. Presuming this to be the case, it has, however, vet to he definitely demonstrated whether it was for the purpose of aiding these reptiles in en- counters with individuals of their own species, or to protect them from the attacks of contemporary carni- vorous dinosaurs, such as the Dryptosaurus (or Laelaps), the Cretaceous representative ol the well- known Megalosaurus of the Oolites. Professor F. A. Lucas, who has paid much attention to the restoration of extinct animals, is in favour of the former alterna- tive, as is evident from the following passage : — " So long as Triceratops faced an adversary, he must Skeleton of the Horned Dinosaur (Triceratopi promts), from C. W. Qilmore, Prae. V S. Nat. Museum, 1905. the food of Triceratops is considered to have been formed by soft, succulent vegetation Although no attempt has been made to reproduce it in the restoration of the skeleton, it was believed by Professor Marsh that during life the body was protected to a certain degree by bony armour. This idea is based on the fact that various spines, bosses, and plates of bone have been found in association with the re- mains of these dinosaurs. To assign these fragments of armour (presuming, of course, that they really be- long to the Triceratops) to their proper position on the body has not at present been found practicable, although it was suggested by Professor Marsh that some were probably situated on the back behind the bony curtain of the skull, while smaller ones may have defended the throat. In a restoration of the creature attempted by an American artist the spines arc alto- gether omitted. have been practicallv invulnerable, but, as he was the largest animal of his time, it is probable that his com- bats were mainly with those of his own kind, and the subject of dispute some fair female upon whom rival suitors had cast covetous eyes. What a sight it would have been to have seen two of these big brutes in mortal combat as they charged upon each other with all the impetus to be derived from ten tons of infuriate flesh ! We may picture to ourselves horn clashing upon horn, or glancing from each bony shield until some skilful stroke or unlucky slip placed one com- batant at the mercy of his adversary .... " A pair of Triceratops horns in the National Museum (at Washington) bears witness to such encounters, for one is broken midway between tip and base; and that it was broken during life is evident from the fact that the stump is healed and rounded over, while the size of the horns shows that their owner reached a ripe old age." March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. In connection with the concluding part of the last sentence, it should be mentioned that reptiles, like fishes, but unlike birds and mammals, continue to grow throughout their entire span of life, so that unusually large bodilv size is, at all events as a rule, an indication of advanced age. As regards general appearance, Triceratops may, perhaps, be best described as a rep- tilian rhinoceros, with the proviso that the tail was much larger and thicker than in that group of animals, and passed insensibly into the body, as in reptiles gener- ally, while the number and arrangement of the horns were different. To imagine what colour the creature may have been in life is, of course, mainly, if not entirely, a matter of pure conjecture. From the prevalence of slaty huts in giant living mammals of the present day, such as elephants, rhinoceroses, and hippopotamuses, Professor Lucas is, however, inclined to believe that similar tints may have obtained among the giant reptiles of former days. "So," he writes, "while a green and yellow Triceratops would undoubtedly have been a conspicu- ous feature in the Cretaceous landscape, from what we know of existing animals, it seems best to curb our fancy, and, so far as large dinosaurs are concerned, employ the colours of a Rembrandt rather than those of a sign-painter." As already mentioned, the head of the Triceratops is so vast in proportion to the rest of the animal that it might seem a difficult problem in mechanics to explain bow it was adequately supported in life. The solution of the problem, according to the researches of the American palaeontologists, is apparently to be found in the great posterior fringe of the skull, which served not only as a means of defence, but acted as a counter- poise to the enormous weight of the fore-part of the skull, and likewise afforded ample space for the attach- ment of the mass of muscles and ligaments necessary to support and move the enormous head. As a matter of fact, the centre of gravity of the skull has been found to be situated behind the eyes, so that the head was well balanced on the anterior neck-vertebra'. It may be added that, as in whales, several of the vertebrae of the neck were more or less completely welded to- gether so as to afford additional support and stability for the attachment of the muscles. Of course, this implies restriction of mobility in the neck, but as this was already brought about by the existence of the oxer- hanging frill itself, no additional detriment was in- volved. ===^= The Observation of Meteors and Meteoric Showers. By \V. F. Denning. THERE is SO much to be said with regard to this sub- ject that it can hardly be comprised within the limits ol a short paper. If photography could now effectually take tin- place of visual observation we might luck for more accurate results, but, unfortunately, we still have to depend mainly upon rough eye estimates of position. It will be important to determine « hether tin- Ho. a ids. Aquarids (May and July), Leonids, Geminids, and sonic other rich Streams, exhibit a shitting or fixed radiant. Tin' I'erseids and Lyrids have centres becoming dis- placed from night to night, while tin- Orionids form a stationary radiant. Fresh evidence should be gleaned as to the apparently long duration of a greal number ol minor systems ami the unchangeable situation of their radiant points. Aie the latter identical in position during their prolonged activity? The principal periodical displays should be observed from year to year, and the date, hour, and visible strength of their maxima carefully noted. Do the Andromedids form an annual display simi- larly with the Perseids, Leonids, &i . ? Fireballs should be precisely and fully recorded whenever they are seen, both as to their paths amongst the stars and the durations of their flights. These brilliant objects are usually directed from radiants in the western half of the sky, and move slowly in orbits overtaking the earth. As they often appear at times when regular meteoric observers are not watching the heavens, astronomers generally should combine to re- cord and communicate the necessary data for the com- putation of their real paths in the air. I have often thought it would be a good plan to form a society specially devoted to the observation and dis- cussion of fireballs. The society need simply consist of gentlemen who would undertake to record and re- port such large meteors as they see either casually or during regular observation. These objects are some- times not fully recorded, and many are not publicly notified at all. Thus numbers of them escape suitable investigation every year in England alone. If observers made it a practice of supplying prompt, ample, and accurate information of such conspicuous meteors as they witnessed, the materials would soon form a sub- stantial gain to meteoric astronomy. For the detection of the ordinary shower-radiants of shooting stars individual observers are recommended to pursue long watches habitually. The great majority of meteoric showers are so feeble that they will escape n cognition unless the search for them is very keen and pei severing. A single observer is capable of doing a great deal of useful work, but must, necessarily, do it in a very thorough manner, or the data secured is sure to be meagre. But an experienced and naturally- talented man will certainly derive more exact and trust- worthy results than any combination of individuals. One amongst the latter may lie very inaccurate, and the incorporation of his results will spoil the whole collection. In a cloudy climate like England, however, an observer working single-handed cannot achieve much, but it is astonishing how many materials can lie gathered by a person who watches during the whole night and avails himself of every opportunity presented. It is particularly with regard to fireballs that I trust some effort will soon be made to secure more numerous observations. The necessity lor this will be obvious when I mention that during the last three months of roo6 I received, or read published, descriptions of 45 large meteors seen in England. Yet only in three or four eases were duplicate observations forthcoming. If some organised plan were followed in collecting data concerning fireballs I feel certain that instead ol some half-a-dozen of their r< al paths being computed annually we should soon be in a position to increase the number to 30 or 40, and this would represent a very important addition to this interesting branch of science. Planetary Chart for 1907. Messrs. Cari Zeiss send a sheet containing particulars of tnetarj positions prepared from the specification of R, 11. Bow, ol Edinburgh. Two charts are presented, one showing the declinations at any given date, the other iie,ht ascensions. [laving found the R.A. and Decl. for an) date from these two curves, the place ol the planet is then plotted \ the Latin poet, Lucretius. According to this theory, the primitive condition of things was atomic. At first these atoms were at rest, distributed uniformly in respect of average density through a sphere of a thousand times the size of the earth. Lucretius held that the atoms had in them the inherent power of motion in parallel lines, but his theory fell through when the parallel motion was trans- formed into jostling and solidifying. But Lord Kelvin considers that each atom would have a velocity to the centre, until some came so near one another that mutual molecular forces brought about combinations. At that stage the density would be considerably less than one-tenth of the density of water. When the density became so great that the atoms jostled against each other, concrete matter began to be formed. There would be an immense crowd of atoms becoming denser round the centre, and jostling one another with increasing force, until the pressure be- came eased by a reactionary rebound outwards, followed by several rapid alternate augmentations and diminutions of the density, until ultimately molar steadiness was nearly reached. This resulted in a vast fluid mass at a very high temperature, which gradually became lower by radiation in waves of ether in all directions outward. There would then ensue a raising of the central temperature by the increased pressure in that region, caused by the shrinkage of the boundary and work done due to contraction. When the temperature of the central region reached its maximum and began to diminish, the whole mass would go on cooling in the still liquid state, till, at the surface it became frozen solid. This denser material resting on the liquid within would, through time, have serious changes on account of the equilibrium being unstable, and large portions of the crust would break away and sink in the liquid. Through time this process, irregularly con- tinued, would go on, until the interior, still liquid, be- came blocked with masses of solid rock of all shapes and sizes. This he considers to be something like the state of the crust and interior of the earth at the present moment. Volcanoes and earthquakes were produced by the settling down of the denser solid material, and the squeezing outwards of the lighter still molten rock. Volcanoes might be expected to continue so long as there was any molten rock in the interior, though he is of opinion that solid matter constitutes much the greater part of the whole mass of the earth. And, even after all the molten rock has been squeezed out in the forms of volcanoes, and has formed solid lava, there would still be a shrinkage of the hot, solid interior, which would leave cavities beneath the cool surface of the earth. Earthquakes would then occur on an in- creasing scale of ^magnitude, as volcanoes decreased. This would go on until the very central region was COOled— till the whole earth became solid. All this, of course, would depend upon there being no violent colli- sion of the earth with another globe, when " the ele- ments would melt with fervent heat." According to Lord Kelvin's theory, there can be earthquakes without lava, only subsidation. The crust of the earth is eool and hard, with an interior increasing in temperature. Slow though it be, there is an escape of heat. The interior must be shrinking more than the crust. The hard outer crust would gradually be dragged inward and vast cavities would be made. The solid earth being- undermined in some places seemed to be an explanation of earthquakes. However, alter an earthquake on a large scale there would be a lowering of level, or an absolute engulfing, as was the case with the small island off the north-west coast of Sumatra. Great sinkings of the earth are noticed after these terri- ble phenomena, and, by the violent action, while some part subsided, another part was tilted up. After the Indian earthquake of 1897 there were very decided changes of level, some parts rising up and others sink- ing down. In a recent earthquake in Japan half a valley was thrown down 20 feet. Accordingly, Lord Kelvin concluded that earthquakes were due to the earth having become undermined, and parts of the solid crust falling into the underground cavities, thus somewhat lowering the surface level. J. G. Mc. P. Obstruction to Greenwich Observatory. The committee appointed to inquire into the working of the County Council generating station at Green- wich has recently presented its report. They recom- mend : (a) The questions of vibration and obstruction by chimneys to> be reviewed after two years' work with the second part of the installation. (£) The second part of the generating plant to be equipped with turbine machinery of a perfectly balanced type, (c) When the second portion is available, the reciprocating engines are not to be used after 10 p.m., and shall be restricted in use after 8.30 p.m. (d) The two chimneys now being built not to be higher than 204 feet above O.D. (c) The gases discharged not to be materially hotter than 2500 F. (/) No further extension of the station beyond the 20,000 kilowatts at present contemplated. The monthly meeting of the Royal Meteorological Society was held on Wednesday evening, the 20th ult., at the Institution of Civil Engineers, Great George Street, West- minster, Dr. II. R. Mill, President, in the chair. Mr. Ed- ward Mawley presented his report on the phenological observations made during 1906 by observers in various parts of the British Isles. The most noteworthy features of the weather of the phenological year ending November, 1906, as affecting vegetation, were the dry period lasting from the beginning of June until the end of September and the great heat and dryness of the air during the last few days in August and the first few days in September. Wild plants came into flower in advance of their usual dates until about the middle of April, after which time they were, as a rule, to about the same extent late. Such early spring immi- grants as the swallow, cuckoo, and nightingale reached these islands somewhat behind their average dates. The only deficient farm crop, taking the country as a whole, was that of hay, all the others being more or less over average. The vield of apples was about average in all but the North of England and in Scotland, where there was a very scanty crop. Tears and plums were everywhere very deficient, whereas all the small fruits yielded moderately well. As re- gards the farm crops, the past year proved even a more bountiful one than that of 1905. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. 53 Features of the Earth and Moon. Craterlets and Canals. (Continued from page 30./ We give some further illustrations from Professor VV. H. Pickering's " Lunar r.nd Hawaiian Physical from below. Analogues of the first two kinds are to be found in Hawaii, though the Hawaiian craters are comparatively so small that the cen- tral cone inside them is rare. Our first figure represents a portion of the middle crater of Mokua- weoweo. Somewhat nearer them the centre is shown an active cinder cone composed apparently of a medium- sized crater and two or three smaller ones upon its rim. The crater Fig. 1. — Mokuaweoweo M t'rjm Professor H. H. Pick, Features Compared," which is included Memoirs of tlu- American Academy. The floors of the craters on the moon "are, Profes- sor Pickering observes, of three kinds. Either they are furnished with a cen- tral peak, like T y iho, or they contain one or more smaller cra- ter-. Hot 1 .11- 1 1 a 1 ; or, « ithoui I 1 Ml detail - 111 which case it appears pro- bable that final floor was melted by a second dark lava flood anion"- the called Kil- au e a I k i, shown in Fig. 2, also repro- duces the c ra t e rle t c haract er- istic. The walls of KU- auea Iki are very steep, but can be descen ded with care. The floor is level, one- quarter of a mile in dia- meter and 750 feet be- low the rim. X u m erous small crater- lets are secu- larly over this floor; and the rj complete them is shown in the illust ration. Its height was 15 feet, and the diameter of the rim, which was composed ol lava of a ropy appearance, auna Loa. Lunar and HawaiianiPhytical mpartd." I ■£ ^. Craterieta Kiiauea Iki. 54 KNOWLEDGE & SCIENTIFIC NEWS. | March, 1907. was 25 feet. A stream of lava had poured from the summit, l>ui had not i^ni far beyond the rim. There may have hem as mam as 50 rudimentary craterlets scattered over the floor, in all stages ul growth, Irom a lava would have completely destroyed them, forming a series of crater pits, into which the lava would have subsequently retreated. In the south-eastern portion two such piis were found, perhaps 30 feet in diameter, Fig. 3.— Pinnacles Maie Imbrium. hardly-noticeable elevation to the complete craterlet shown in the figure. . . . "If the volcanic forces beneath these craterlets," observes Professor Pickering, " had been more intense, it is probable that the issuing' Fig. 5.— Crack, KHauea. Fig. 4.— Ariadaeus Rills. down which the lava had poured, but had solidified without filling them up. After the craters, among the most important features of the lava floors, are the elevated formations — the spiracles, pi n nac les, and ridges. When the gases work their way up to the sur- face they escape by little blow- holes. In so doing they often carry small quanti- ties of lava along with them. This lava quickly hardens on reaching the surface, and builds up around the aperture a tube, which P ro f e sso r P i cl :l0W. ( (tiler narrower rills apparently of great depth are found on the moon. The general view that they are simply cracks in the lunar surface is accepted by Professor Pickering as correct. They occur most frequently in formations of the secondary period; that is, in the dark surfaces; or, if found in the primary formations, it is where the surface has apparently been softened, and partially flattened out by the application of heat, as in the present instance. Rills are frequently found on the edge of the lunar lava seas. A large crack is found in Kilauea in precisely this position. It is from six to eight feet wide, and from 20 to 30 feet deep near the bridge. It is about a mile in length. A crack 5 to 20 feet in breadth, and 40 to 200 feet in depth, and 16 miles in length is located south-west of the crater, and a similar one lies parallel to it. The cracks themselves have been partially filled up, but one said to be 1,500 feet in depth, is situated not far from the sixth crater near Kelanea. Professor Pickering devotes some attention to the question of water and vegetation on the moon. "It is," he says, " a favourite argument of those who denv that water ever existed on the moon, to say that if such were the case signs of erosion would be found on its surface. In the case of the earth, where vast bodies of water are present, these signs are very pronounced in the eroded valleys of mountain regions and the alluvial plains of the more open country. When we search the coarser detail on the moon no such signs are found. . . . But, if the moon ever possessed any water at all, it must have been in comparatively small quantities, and we should accordingly look among it^ finer detail for any evidence of its former existence. Fig. 6 represents Theophilus, a crater 64 miles in dia- meter. The central peaks rise 5,000 to (1,000 feet above the crater floor and are indented by numerous deep vallevs, four being clearly shown in the photograph. It is believed that these valleys are due to erosion, and are analogous to those shown in Fig. 7, which repre- sents a mountain ridge behind Honolulu. The pre- l:lg. 7.— Kroslon Vallcys'in Hawaii. 56 KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. cipitation cannot have come from a general atmospheric 1 in ul. Hum. hut more likely from steam expelled from the Fig. 8.— Terrestrial Valley or Canal near Kilauea. chain of the Andes lie along a straight " crack " reach- in- from Southern Peru to Terra del Fuego, 2,500 miles m length. I he volcanoes of the Aleutian Islands lie along a curved crack equally long. Since other shorter lines of volcanoes are very numerous on the earth, and since countless others ex- isted in former times, the cracks on the earth's crust must be exceedingly numer- ous. Every mineral dike and vein, in- deed, bears witness to this fact. There is no reason why terrestrial cracks should not be as numerous as those on the moon. In the case of the earth they have usually been closed, some- times by liquid matter from below and sometimes by surface denudations. There is one openings of the spiracles in the central peaks themselves. The lunar day is 29.V terrestrial days in length, and, from the standpoint of climate, might almost be called a lunar year, for the temperature rises from some 250 degrees below freezing to a height as great as that experienced on the earth's equator, in the course of 14 or [5 days of sunshine. It has been observed that some spots on the moon grow darker in this period, and Professor Pickering attributes the darkening to the springing up of vegetation. In the crater of Eras- tosthenes, which is about 40 miles in diameter, he has perceived two dark spots on the crater floor, and has noted that these spots change, disappear, or increase, as the long lunar day progresses from sunrise to sunset. There are two snow-white central peaks in the crater, and the dark spots (of vegetation?) are joined by lines, which, to Professor Pickering's mind, resemble the canals of Mars. In studying Erastosthenes in 1904 Professor Pickering found its interior seamed with numerous fine cracks. Watching some of these cracks soon after the sun rose on them he was able to see them broaden out and change gradually into canals. It is his belief that the cracks gave out water vapour, which fertilised the vegetation along their sides and in their neighbourhood, and that it was the growth ol this vegetation which produced the appearance of a canal. A further inference is that the canals on Mars, which become more clearly visible at some periods of the year, owing- to the melting of the Martian Polar ii e cap and the flooding of the waterways, are similar cracks on the surface of Mars. Cracks of the kind occur on the moon. The largest of them is that known as Sirsalis, which is 400 miles in length. It is possible also that they exist on the earth, though they are not readily discernible. It has sometimes been supposed that tern -trial volcanoes lie .deny subterranean (-racks that do not reach the surface. The volcanoes "I the great Fig. p.— Sinus Iridum. A Crater Ring on the Moon. crack, however, which comes to the surface in various places in Eastern Asia and Western Africa, and stretch- ing from the Dead Sea to Lake Nyassa, reaches the enormous length of 3,500 miles That is about the same length as the longest of the Martian canals. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. 57 Halley's Comet. By I-'. VV. Henkel, B.A., F.R.A.S. (Late Directot 1 < Markrei V ... 'I he .shortly expei ted return of this well-known object, which was the first of these bodies known to move in closed paths round the Sun, and the remarkable phenomena attending its last appearance (in 1S35 and 1836) render Halley's Comet a peculiar object of in- terest at the present time. Newton, in the third section of the Principia, first showed that a body moving under the influence of a force varying inversely as the square of the distance from the centre of force, will describe one or other of the curves known as the " conic sections," i.e., eith 1 an ellipse (or circle, as a special case), a parabola, or a hyperbola. These three curves may all be obtained by cutting a cone in different ways by a plan.-, but perhaps they may be more intelligibly defined to the non-mathe- matical reader as obtained by throwing the shadow of a circular disc upon a plane, such as the surface of a table. If, however, the disc is held parallel to the table, we shall gel a circle ; if it is held edgeways to the light, the shadow will be a straight line. If now we raise our disc so that its highest point is on a level with the source of light, we shall get a curve known as a parabola, which will be oval at one end, but the two sides will open out. If now we hold our disc still higher, we shall get another curve still, whose two sides will separate even further from one another. This curve is known as the hvperbola. Whilst the planets move in ellipses, so little differing from circles that if represented on paper the deviation is not perceptible, on the other hand, most comets are found to move in orbits so nearly parabolic that only in a few cases are they known to be otherwise. A great cornet which appeared in 1680, and approached very close to the Sun, was the first whose path was calculated as a parabola, though there is some reason to believe that it was not truly so, but an enormously elongated ellipse. In 1682 a comet was observed by Newton. Halley. and others, and on examining the circumstances of its motion, Edmund Halley computed its orbit on the sup- position that this was a parabola, Comparing his results with observations of previous cometSi for which purpose it was necessary lor him to compute their orbits from the necessarily imperfeel observations of earliei times, he found that in 1531 and 1607 comets had ap- peared which followed si 1 nearly the same path as this one that he ventured to assert its identity with them. and to predict its return in a period of about 75 years. It was afterwards ascertained that comets had been seen in 1066, 1378. and 1456 whose paths were the same as thai of the comet oi 1682, and it is now known that all these were apparitions oi one and the same body. In 1066 its appearance was figured on the BayCUX tapestry, and it was regarded (after the event) as an omen of the Norman Conquest. In [456 the comet is said to have been of extraordinary splendour, its tail (10 degrees long, and it is slated that a papal bull was fulminated against tin- 'Turks and the comet and it was ordained that the bells nl all churches should be rung at mid-day. Athough Halle) had predicted its reappearance, he did not live to observe this himself, dying in 1742, at the age oi 83, aftei having been Astro nomer Royal for 23 years. He pointed out that the comet must have passed very near the planet Jupiter in the interval between 1607 and 1682, and its velocity increased, thereby resulting in a shortening of its period volution. Thus he concluded that, whilst the interval between 1607 and 1682 was only 75 years, the following revolution would probably take a longer time; but the then state of Mathematics did not enable him to make the necessary calculations to determine this with accuracy. Were the Sun and comet alone existing in space, the hitter's path would be an exact ellipse, and the period of its revolution always the same. This is, however, not the case. Besides the Sun I tlie planets, and these, by the law ol gravitation, attract, and are attracted by, one another, and other bodies. Their masses, however, being very small, in comparison with that of the Sun, the general nature of the paths pursued by planets and comets is not changed by this action ; but deviations nevertheless arise, which are the more perceptible as their masses are greater and their approaches more close. Thus Jupiter, the giant planet of our system, whose mass is about lT,\TTJthat of the Sun, has at tin greater effect on comets when near to him than the Sun itself. Lexell's comet of 1770 must have been at one time fifty-eight times less distant from Jupiter than from the Sun, and so the planet's attraction (inSr. that of the Sun) must have been three times greater. "The celebrated Ciairaut. who so greatly advanced the science of astronomv by his work on the Moon, as well as by his researi he- in pure Mathematics, undertook the great labour of calculating the effect ol the action of the planets upon Halley's Comet for a period of about 130 years, and in a memoir presented to the Academic des Sciences, at Paris, he predicted the date of perihelion as the 1 St h April, [759, subject to an uncertainty of about a month. As the result of his calculations he estimated that the period "I revolution of the comet was increased by 100 days on account of the action of Saturn, and 518 days by Jupiter. It was first seen by Palitsch, a Saxon peasant, about the end ol 1758, and came to perihelion on March 12, 17511, just a month earlier than the time assigned by Ciairaut. Before its next return the orbit was calculated by no less than lour mathematicians, Damoiseau, Pontecoulant, Rosen- berger, and l.ehmann. and they all agreed in giving a day in the month of November, 1835, as the tin its perihelion passage It was first seen at Rome early in August of that year, aim\ was visible up to the 16th November in the Northern Hemisphere. After this, passing its perihelion on that day. it was seen at the Cape and at Melbourne up to the early part of May, 1836, when it finally disappeared from view. Very careful observations and elaborate draw- ings oi its appearance were madeb) Sir John Herschel, who was then in South Africa. At first it presented the appearance of an almost round nebula, having a bright nucleus not quite at its centre. By the beginning ol October. [835, a small tail appeared, and this a length of about 20" by the middle ol" the month. this the tail diminished, so that before the time ol" lion 1N1 \ niiui in it had again disappeared. On the 2nd ot October, the dav when the tail was first seen, an emission of light was seen coming from the IS, on the side presented towards the Sun. 'This .•mission ceased for a time and then recommenced on the 8th oi that month. At this time one 1 i ived w hat he called a " second tail," in a direct 101 posit, ■ to the original tail- thus presented towards the Sun. The sl\a|H' and brightness of the emanations con- s8 KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. tinualiy varied from the 3 1 1 1 to the (2nd of October. At one time two or three emanations were seen to issue in different directions, these having forms sometimes like thai "I .1 gas flame coming from a Rattened opening, at other times only slightly divergent, and again occasion- ally only one jet was seen. When more than one such jet or emanation was visible, the principal jet ol light oscillated in direction tn and fro on either side of the line directed towards the Sun. " like a compass needle thrown into vibration and oscillating about a mean position." Sir J. 1 lerschel concluded, from his own ob- servations and those of others, that the matter of the nucleus is largely converted into vapour by the Sun's heat, and escapes in jets and streams from the parts turned towards the Sun. This matter is, however, pro- vented from proceeding in this direction by some force directed from the Sun, much more powerful than gravi- tation (and repulsive). Being thus repelled from the Sun with considerable velocity, it must leave the nucleus altogether, and, consequently, at each approach the comet must lose a portion of its substance, for the feeble attractive power of the nucleus will prevent this matter being retained within the comet's sphere of at- traction, and it will be too far away to be re-absorbed afterwards. ITius it is probable that at each ap- parition the comet will be less conspicuous. After passing its perihelion, the comet was not seen again till near the end of Janur.ry, when it had no longer a tail, but was seen as a small, round disc, surrounded by a " coma " or nebulous envelope. As the comet gradually receded from the Sun this coma disappeared as though absorbed into the disc, and this latter increased greatly in size, so that during one week (from January 25 to February 1) it increased in volume 40 times. This in- crease of size continued, so> that mainly from this cause it became invisible, its illumination iDecoming fainter and fainter as its size increased. The shape of the disc changed gradually from a nearly' circular form to that of a paraboloid. The nucleus meanwhile re- mained nearly unchanged, but the ray or jet pro- ceeding from it increased in length and brightness, its direction being along the axis of the paraboloid. " If," says Hcrschel, " the office of the jets was to feed the tail, the office of the ray would seem to have been to conduct back its successively condensing matter to the nucleus." The comet's envelope and ray gradually faded, and as last seen it had the same form as in the previous August, viz., that of a small, round nebula, with a bright point near the centre. In all, it was visible from the 5th of August, 1835, to the 5th of May, 1836, a period of 9 months. The period of revolution of this comet is given in Herschel's " Outlines of Astronomy," as 27,865.74 days, so that, since it passed its perihelion on the 15th of November, 1835, it should again return to this position on March 2, 1912; but on account of the considerable disturbing action of the planets Jupiter, Saturn, and Uranus, the actual date may differ considerably from this. So eccentric is the position of the Sun in its orbit, that whilst at perihelion the comet's distance from the Sun is about 0.586 of the earth's distance, or about 55 millions of miles, it recedes to a distance of 35.4 times that of our earth, or about 3,300 millions of miles, con- siderably greater than that of Neptune. Whilst the planets all move in orbits lying nearly in the same plane, the comet's orbit makes an angle of 170 with the Ecliptic (plane of the earth's orbit), and its motion therein is in a direction contrary to that of the planets (and of most of the other short period comets), or is retrograde. Whilst the planets move in a direction op- posite to the hands of a clock, as seen from our northern latitudes, the comet of Halley moves in the "clock- wise " direction (as shown in the accompanying dia- gram'). This comet, as also five others, viz., Pons' Comet, seen in 1812 and [884; Olbers' Comet, seen Perihcl Aphelion ., 35-4 Longitude of Perihelion 305 in-i , ,, ascending node 55°(&) in 1 81 5 and 1887; De Vico's Comet of 1846; Brorsen's Comet of 1847, and Westphal's Comet of 1852, passes near Neptune's orbit at its aphelion, and these comets are sometimes known as Neptune's family of comets. If at any time a comet enters our system from an infinite distance, moving in a parabola under the Sun's attrac- tion, it will have its motion either accelerated or retarded when it comes near any of the planets. The smallest increase of velocity will change the parabolic orbit into a hyperbolic one, the smallest decrease will convett it into an ellipse. In the latter case the comet will become a permanent member of our system. This it is possible is what has actually happened, and the converse case of a loss seems also to have occurred. A comet was discovered in 1770, and was shown by Lexell to move in an elliptic orbit, with a short period of about 5^ years. It was, however, never seen again, nor were any former records of its appearance to be found. Lexell, however, showed that in 1767, when at its aphelion, or furthest from the Sun, the comet must have been fifty-eight times nearer to the planet Jupiter than to the Sun, and that then the planet's attraction on it was three times that of the Sun; that in all probability it had been moving in a parabola, which orbit was con- verted into an ellipse bv the planet's action. He further showed that since the aphelion was close to Jupiter's orbit and the comet's period 5 1 years, that of Jupiter being n years, at the end of two revolutions of the comet and one of the planet, they would again be close together, 500 times less than their distance from the Sun, so that in all probability the comet's orbit would become again parabolic or hyperbolic. Thus he anticipated its eventual disappearance, and, in fact, it was never again seen. Laplace and Leverrier later showed, however, that Lexell 's results were liable to considerable uncertainty. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. 59 Although, as we have stated, the motion of a comet is greatly affected by the proximity of a planet, the latter, on the other hand, seems quite unaffected. Thus, the comet of Lexell approached so closely to the planet Jupiter that, had its mass been in any way considerable, both that planet and its satellites would have had their orbits completely changed, the comet's distance from Jupiter being, when nearest, less than that of the fourth satellite (the furthest of those dis- covered by Galileo in 1610). Nevertheless, not the smallest measurable derangement was observed, so that the mass of the comet must have been much less than that of any of these satellites. This seems to be a general rule, no perturbations due to a comet having been ever perceived for any planet. Vet the volume of some comets being at times greater than that of the Sun itself, the density of the materials composing them must be extremely low. This is also evident from other considerations. Small stars have been distinctly seen through the head of a comet, even through the nucleus, without perceptible diminution of brightness. In the case of one comet, known as Encke's, from the name of the discoverer, there is reason to believe that its period of revolution is diminishing gradually, and that it is slowly getting nearer to the Sun, as though aoted upon by some resis- tance to its motion. This has been supposed to be due to the " luminiferous ether," but since this retardation seems to have become much less of late years than formerly, and so far no other comet seems to have its motion affected in a similar way, there is considerable doubt about this conclusion. By Kepler's third law, the periodic time of a body moving round the Sun is known from its distance from that body. (The squares of the periodic times are as the cubes of the mean distances.) Thus, a resisting medium, by diminishing the comet's velocity, gives the Sun more power to draw it towards itself, and so, lessening its distance, causes its period to become shorter. So unless the comet be dissipated by loss of material, it will some day fall into the Sun. Many interesting problems are presented to us by these bodies (of which Halley's Comet is one of the most remarkable and interesting). The question as to the existence of a resisting medium, the nature of the repulsive force (supposed by some to be electrical, which is at times much greater than the gravitational attrac- tion), the condition of the matter composing the comas and the tails, and the origin of these bodies, are all matters concerning which we know but little at present. Many recent writers have revived Clerk Maxwell's idea of " radiation pressure " with regard to the phenomena (if comets' tails. Light being regarded as an electro- magnetic phenomenon, its incidence on an absorbing substance causes a pressure on the latter. The late Professor Fitzgerald suggested this light pressure as the cause of comets' tailsi and observed that each different gas would give rise to a separate tail, owing to the different size and density of its molecules. Since only a small part of the radiation falling on gases is absorbed by them, Arrhenius supposes that the matter lepelled by the light pressure is not gaseous, but rather consists of tine particles, condensed from the gaseous emanations. In making some further investigationSi Schwarzschild arrived at the conclusion that light pies sure is sufficient to account for a repulsive force twenty times as great as gravitation on the cometary tails and appendages, but not lor a greater amount of force. Since in some cases a repulsive Force as much as jo times that of the gravitative attraction has been ob- served, the light pressure theory is insufficient to account for these. Of other theories as to cometary appendages, we may mention that outlined by Mr. Boys, in his presidential address to Section A of the British Association, 1903. He suggests that radio-active substances in the nucleus may be the cause of these phenomena. If the Sun be electrically charged, the rays will be repelled from the nucleus so as to form a tail, and the different kinds of rays given by radio-active substances would give rise to tails of differing curvatures. It has already been stated that though the mean period of Halley's Comet is nearly 77 years, yet, on ac- count of planetary perturbations, the actual interval from one return to the following may differ very con- siderably from this. In 1862, Dr. Angstrom published a paper in which he deduced a mean period of 76.93 years from a discussion of all the observed perihelion passages, and staled that this period is affected by two large inequalities. Calculating from his empirical (i.e., observational) formulae. Mr. Crommelin has ob- tained the date 1913.08 for the next return to perihelion. The late Comte de Pontecoulant, however, in 1864, pub- lished the results of his calculations, giving the date of 1910. May, for the next return, a difference of nearly 2§ years from Angstrom's result. Messrs. Cowell and Crommelin, of Greenwich, are at present engaged in in- dependently computing the perturbations of this comet, following Pontecoulant's method, and the present writer has also done a little in this direction. Some obvious errors in the values given by Pontecoulant for the change of eccentricity have been detected) and the perihelion distance is nearly the same (0.59, the earth's distance from the sun being 1.001 as at the last return. whereas Pontecoulant made it considerably greater (0.68). However, they have arrived at the main result, that the time of return given by Pontecoulant (1910, May) is correct within a month, but it may be a few weeks earlier; consequently Angstrom's curve is alto- gether wrong for this return. Thus they consider his two inequalities to have a very doubtful existence, and that it is possible many of the earlier returns have been wrongly identified by Hind, whose results Dr. Any- used. Practical Aerodynamics And the Theory of Aeroplanes. II. HEAD RESISTANCE TO A BODY MOVING THROUGH THE AIR. By Major B. Baden-Powell. Any body which is being rapidly driven through the air, whether it be the main body of the apparatus or the blades of the screws, win^s, or other propelling ap- pliances, is acted upon In three different forces (in addition to gravity), which tend to retard its speed. Muse .in-: First, the head resistance, caused by the inertia oi the particles ol air w hich have to be displaced in oulcr to make way tor the body. Second, the negative press 01 suction due to the partial vacuum which is formed behind the body, and the air which has been displaced taking time to flow back to till tin- space winch it originally occupied. Third, tin or skin friction. \s Lord Kelvin has said. "In Nature everj fluid has some degree ol viscous resistance to change ol shape," which als,. a, counts for these opposing fo 6o KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. h will readil) be understood that the pressure on .1 bod} being pushed against the air, or falling vertically through it, is exactly the same as il the bod) were held stationary and .1 stead) current ol air, such as wind, be 1I1 i\ en against it. In considering head resistance we will first take the case "I a plain- surface propelled perpendicularly to the line of advance. The problem to be decided is, what is the force opposing the progress ol the piano as com- pared i" the speed and ana.-' This is a mosl important consideration, as it is on this that all our calcula- tioi s must be based. When we come to investigate the pressure developed on inclined or curved surfaces, it will be seen that these arc but a certain definite proportion ol the pressure that would be imparted to a plane sur- face nl similar area moving at right angles. Supposing we find that to propel a given mass at a certain speed it becomes necessary to apply a steady push of one pound, it is e\ ident that in order to increase that speed it will be necessary to apply more force. Newton, by noting the time taken by spheres in fall- ing from the dome of St. Paul's Cathedral, concluded that the resistance of the air on the body is proportional to the squari- ol' the velocity. Later experiments have shown this law to be approximately true. This is to be expected, since it we imagine a plane moving against the air at a given rate, if its speed be doubled it will strike the air twice as hard, but it will also pass over double the distance in the time, and will, therefore, strike twice as many particles of air, hence the pressure or force required will be four times as great. There is, however, still some doubt as to whether this law applies when the body is travelling at com- paratively high velocities. Experiments made on the resistance offered by the air to projectiles moving at speeds ol 2,000 or 3,000 feet per second tend to prove that the resistance increases in a greater ratio than at rates below a hundred miles an hour (14(1 leet per second). But it is only the latter that we need now be concerned with. To get at a proper working formula for computing the resistance of the air, we put P=Kv2; that is, the pressure in pounds per square foot equals the square of the velocity in miles per hour multiplied by a certain constant K, which has not yet been very exactly deter- mined. A number of separate experiments have been made to solve this point, but the results have not been in per- fect agreement. It may be desirable, considering how- important the results are to the subject, briefly to- re- capitulate what has been done in this line, and the con- clusions come to, since, as far as I know, no connected account of these has hitherto been published. The resistance of the air was first carefully investi- gated by Robins' in 174.2. His experiments were chiefly directed on tin- investigation of the resistance offered to bullets fired from a musket, which at that time was a matter almost entirely ignored. Later on he constructed a " whirling machine," consisting ol a light arm rotated by means ol a weight unwinding a cord wound round its support. On the end ol the arm was mounted a sphere to represent a cannon ball. Smeaton, who had been investigating the lone ob- tainable by means of windmills, shortly afterwards pub- lished a table of wind pressures! which had been communicated to him by Rouse. This was compiled on the supposition that K=.oo5. The table, though pro- ■ "New Prmciplesof Gunnery." by Benjamin Robins, F.R.S.. new edition, to which is added " Subsequent Tracts." 1S05. I '• Philosophical Transartions " for 1759, p. 165. duoed m so uncertain a way, nevertheless was accepted as authoritative, and is often quoted intact to this day in hooks dealing with engineering and wind elicits. Subsequent investigations, however, show that these deductions were somewhat misleading. In [809 Sir George Cayley came to rather different conclusions as the result of his own experiments. 'I he latter were conducted with an apparatus in which a surface ol one square foot was mounted upon an arm about five feet long androtatedb) weights over a pulley. lie found after " many carefully repealed experiments, that a velocity of 11.538 feet per second generated a resistance of 4 ounces, and that a velocity ol 17.10 feet per second gave 8 ounces resistance," which would give a value of .004 and .0034 respectively lor the symbol K. Dr. Mutton1 continued the experiments ol Robins, using the same or a precisely similar machine (which is still preserved in the model room at the Royal Academy, Woolwich). His investigations were more extensive and precise, and will again be referred to. In compiling a table of wind pressures his figures differed slightly from Smeaton's table, giving less force for a given velocity. In these K would work out at just about .004. More recent investigations, which tend to prove a still lower value for K, must be deferred to another article. *„* In the last article (February Knowledge) the title of Mr. Wilde's paper " On Aerial Locomotion " was wrongly printed. I To be continued. 1 CORRESPONDENCE. To the Editors of " KNOWLEDGE & Si [ENTI1 u Xi.ws." Sirs, — I have two thermometers in the same screen, one wet bulb, the other dry. Usually there an- from o° to io° difference between them, 'this morning the wet bulb was the highest by about 2° or 30. I have nut iced the same effect at other times, when the water in which the cotton is soaked was frozen. Why is it? Also, is there usually a wave of high barometric pressure about January 25? I see, in 1904, that there was a record high barometer, or something like it, then. Yours faithfully, Hopesay Rectory, R. J. ROBERTS. Aston-on-Clun, S.O. February 7, 1907. [When the temperature is below freezing-point the wet bulb thermometer requires special attention, as the muslin and conducting thread become frozen and there is con- sequently no supply of water to the bulb. On the occasion referred to above the moisture on the muslin round the bulb was evidently just passing from the liquid to the solid state, and so was at the freezing-point temperature, viz., 32". The mercurv in the wet bulb thermometer would remain at 320 until the freezing process was complete. On many occa- sions— especially in rather damp weather and with the tem- perature of the air not much below tin freezing point — the wet bulb thermometer will remain at 320 lor a considerable time — often for hours— and so be much higher than the dry bulb. During frost tin muslin should be wetted about an hour before the time of observation, so that a coating of ice may be formed round the bulb. With regard to barometric pressure, this is much more variable in winter than in summer, and so in om year il may 1» very high and in another year very low about the same date. .Mr. Roberts mentions January 25, 1904, as the date whin a high baro- metric pressure occurred. Airainst that may be placed January 26, 18S4, when practically the lowest barometric pressure ever recorded in the British Isles was observed, viz., 27.332 ins. at Ochtertyre, near Crieff.- W. M.| • Nicholson' s Journal, November, 1S09. Mathematical Tracts," Vol. 3. by Dr. C. Hutton. 1 8 1 2 . March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. 61 Physics and Biology. 1!\ John Hitler Burke, M.A. (Camb. and Dubl.i. Formerly Berkeley Fellow of Owens College, Manchest The study in recent years of life's origin has come more closelj within those departments ol si ience which deal with the invisible and ultra-microscopic i< rms of matter than with the visible, which are so much more and so vastly complicated. It comes, as 1 have tried to indicate elsewhere, more within the realm of chemistry, or indeed more appropriately physics, than within that of botany or zoology. And it is, perhaps, as remotely connected with these, as these are with human physiology; nay, even (should we say?) with psychology. For the problem of life's origin is one that resolves itself, and is ultimately lost in the grada- tion of the infinitely small; a fact which concerns the physics far more than it does the biology ol to-day. View it as we may, it leads us, as I think, to infer the atomic constitution of vital substance — vital atoms, entities as separate and distinct, and perhaps immutable, as the atoms ol the chemist, or (should we sa\ ':) the electrons of the physicist. No prejudice or predilections, as to what does or does not come within the sphere of any particular science, should be allowed to stand in the wax of developments on these lines: if there are reasons which indicate that the recognised limitations should be ex- tended or removed. Now in dealing with vital phenomena, from a physi- cal point of view, one fact stares us in the face ai h time we approach the problem; and that is, the asym- metric structure of living matter; and the fact that such asymmetric structure has hitherto never been obtained, save through the agency of its vital processes. This is a phenomenon not less than that of life, which baffles the physicist, as much as it dees tin biologist of to-day. And it is undoubtedly one which runs parallel and is concomitant with the phenomenon of life itself. How did the asymmetric structure arise? Is its asymmetric property that which gives the unstable but directive quality to living matter? Is it. and is living matter with it. as persistent, as approximately stable, as the atoms themselves? How are physical principles in the phenomenon of biotic energy or poten- tial life-activity to be explained? The argument, from continuity alone, might lead us to expect that the electron is onl) a halting -1 p in the great scale of being ; and that, whether we should ever succeed in demonstrating it or not, it. too. in its turn will be found to be an aggregate ol smaller units. So on ad infinitum. There i-. however, no actual demonstration of this possible at present. Now, my endeavour has been to show that biophores. the ultimate nuclei or \ital units in their final state, ai aggregates of smaller units. There is a stage through which, like spiral nebulae, on a totally different scale, they musl pas- before being transformed or condensed into stable systems, like chemical atoms. As all nebulae are resolvable into these spiral forms, so the condensing aggregates of electrons not less than those of matter in its grosser states would have to assume the peculiar shape-, or curves, which char- acterise their larger analogues. We must not expect that we shall ever reach the smallest any more than the largest ol things; l"> in the mathematical and physical there is nothing either great or small, but thinking makes it so. The problem of life transcends physics because for man;, reasons it not merely depends upon the ultra- oscopic, but in turn upon the atomic, ultra-cor- puscular, or ultra-electronic, ad infinitum. The electron or corpuscle should be an ?:_ and not an indivisible, unit. On thi ^ basis, the forma- tion of such nebula; and spiral atoms may be conceived. The actual corpuscles which form the planets of the liar systems would seem to be in their turn but aggregates ol smaller units. My chief reasons for holding this view ai follows : — Clerk Maxwell was careful to point out that the variety of phenomena of life could not be accounted for by the small number of atoms in the organic cell. I he chemical atoms, indeed, ol the same element may be regarded as resembling each other only in certain respects, as one individual resembles another. But il they are aggregates of smaller units, a- I have tried to emphasise in "'The Origin of Life," there would be opportunities for variations in atoms, which, as chemical units, are the same. The atoms of the same substance would, so to speak, have merely a family likeness, and there are strong reasons for supposing that the phenomena of life are thus dependent upon the ultra-atomic constitution of matter. A pri analogous to natural selection would ensue. Xow the general physical property ss matter arc explicable, as we know, on the -.apposition that there are small particles called molecules : the chemical properties on the supposition that there are smaller ones called alonis ; tl ical properties on the assumption that there arc still smaller ones called corpuscli ■■lections: and the biological properties. I think, on the assumption that there are yet smaller ones — sin, 1 we --hail s;_,-. such phenomena demand it — of which biophores or biogen are nebular forms. If there are biophores with an asymmetric structure, that asym- metric structure and all its varied properties can ' plained on the supposition only that the electrons are aggregates ol smaller units; an assumption which other phenomena demand. There is nothing unphilosophic in this assumption. And if the atomic theory is to hold in its application to biological, as well as to purely chemical and physical phenomena, the facts of th, demand it. We cannot frame the nebula analog) for electronic systems without postulating that the electrons or corpuscles are aggregates ••! smaller things. The corpuscle may be compared to a planet; the nuclear positive ion to a sun; but il these systems have been formed by condensation, they must In- the condens ol --till smaller thing-. Germ-plasm, that i-. the biophoridse, would thus consist of a nebula of uncondensed matter, ol puscles or electrons in the state of formation, as planets and s ilar S) St ms are c\ olved from atoms. This is not an absurdity, as ma) at lirst sight be imagined. but merel) an extension, and a logical extension, as I venture to think, ol the theory that atoms are such miniature planetary s\ stem 1 1 atoms and electrons may be regarded as the condensed product- ol the primordial substance, which I have called h gen. S • eminent a man of science as Professor Schuster has written in the following terms in discussing this theory ol biogen in its relation to the origin of lit, The discoveries ol the last few years have in one respect inverted our previous idea- <>i the problem of • Mju. '1.5.'. 1 o.i.im.'.c, April 27, njo6. 62 KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. creation. ITiat there was onl) one substance, and thai all matter was ultimately derived from thai substance has, 1 believe, been always a tacitly accepted axiom oi scientific thought. But we look upon the more com plicated structures as having been gradually built up from the simpler ones. Hydrogen being the body which has the lightesl atoms, and other bodies having atomic weights which are approximately multiples ol that of hydrogen, the thought was natural that hydro- gen was, il not the ultimate atom, yet the body which formed the bricks out of which other so-called elements were built up. At last, however, we are able to watch the actual formation of one element out of another, but instead of the more complex bodies being formed out of the simpler one, the reverse is the case, and one of the lightest elements, helium, is evolved from one of the heaviest elements, radium. "Where we can follow the process of evolution, il is therefore the complex body, which, through in- stability, yields the simpler one. Scientific men love to generalise, and it is therefore natural that they should quickly have inverted their former ideas and have begun to look at the must complicated structures as the one which was formed the first.' If this idea is driven to its extreme-— though not necessarily its logical — limits, we should be led to the conclusion that living organism is the primordial element, and that inanimate matter is only the result of the decay of living matter. This I gather to be Mr. Burke's view'. He compares, indeed, the derivation of ordinary- matter from the original bio-clement with the evolution of the solar system, out of the historic, though now somewhat dis- credited nebula. It is undoubtedly a new and an original view, and one that must be taken seriously." I owe to Professor Schuster a deep debt of gratitude for thus emphasising what many of my other friends could not be made to understand. Many investigators are as absorbed in their own special work as they are indifferent to its relation with anything else. I say this in all good faith, appreciating as I do the high ■value an investigator's opinion in his own special, but narrow, line of work may have. But the great discour- agement which it can mete out to any scheme which does not fit in with that which he himself may happen to be engaged in, is not always stimulating or satis- factory. New ideas, no doubt, require to be familiar- ised. If they do not at first seem to be quite orthodox — as new ideas seldom are — or if they are not alto- gether on similar lines with those in which others have been working, the promulgator thereof may expect to have many bricks, like books and candlesticks of old, flung at his wearied and bewildered head. Quite apart, then, from the question as to whether the views I have ventured to put forward are orthodox or heterodox, let us consider them in their relation to the great problem which not merely biology, but physics now presents, the asymmetric structure of living mat- ter and the concomitant or inseparable connection be- tween living matter and asymmetric structure. For as living matter has never been produced from dead mat- ter, as familiarlv understood, so polarising matter has never been obtained except through the intervention of that which is living or has lived. As we say, if the atomic and electronic systems have been formed by a process of condensation of a primordial substance, the transitory stages of spiral nebula; is to be expected. But it may take many thousand years to pass through this transitory stage; even as the astronomical nebula; on the larger scale take many million millions of years to be condensed into a solar system. In such circumstances, then, the atomic ncbukc may, for all intents and purposes, be regarded as entities as much so as the individual atoms; unstable as these may really be. Their spiral nature, however, would in cer- tain circumstances rotate the plane of polarisation ol light ; as, for instance, when the atoms are all right- handed or left-handed. Now such spiral atoms, if they may be so called, will in the course of time be converted into more stable atomic systems, becoming radio-active, and ullimal K inert. The latter being the lightest elements. C*£tr*\ registering balloons in connection with ihe work undertaken at various stations tor the International Committee for researches in the upper air. On July 6, 1905, a rubber balloon sent up from the Meteorologische Zentralstation at MUnchen (Munich) attained a height of 23,000 metres (14.292 miles). The balloon was 1 '■ metres diameter, inflated with hydro- gen. It landed at Deggendorf, having travelled a distance of_ iji kilometres W.N.W., the period of flight being 97 minutes. BOTANICAL. By G. Massee. The Water Hyacinth. Tins beautiful aquatic plant, known botanicall;, as Eichoriiea speciosa, is at the present moment a source of great anxiety to the members ol the Legislative Assembly of New South Wales, owing to its rapid extension in the creeks, lagoons, and more sluggish rivers of that country, thus impeding navigation. When growing in shallow streams or lagoons, it tends to suck up the water, and converts limpid streams into bogs. The plant is a native of tropical South America, and, being very showy, is much cultivated. Its spread in New South Wales is traced to a few plants having been thrown into Swan River by a local resident, who cultivated it as a decorative plant. The water hyacinth is an aquatic, and usually floats freely without being attached to the soil ; when growing in shallow water or swamps the roots grow into the mud. If the mud becomes dry, the plant perishes. The leaves are roundish and arranged in a dense rosette one or two feet high ; the lower portion of the leaf-stalks are much swollen and tilled with air, and serve as buoys insuring the stability of the plant, and preventing its being overturned by wind or waves. The roots form a dense tuft one or two feet long. The flowers are produced in pro- fusion, of a lilac colour, and arranged in clusters like those of the hyacinth, hence the popular name. The plant is re- produced abundantly by stolons or shoots from the parent stem; these stolons, when about six or nine inches long, form a rosette of leases at tin tip, which soon forms a plant as large as the one from which it originated, and in turn produces stolon-, ; |,y such means dense groups of plants of different generations remain organically united, and as the stolons are very strong, rowing boats and barges find it impossible to make headway, ami steamers fare but little better, as the plants become entangled in the blades of the propeller. During floods large masses of the weed are de- tached and carried down stream as floating or half-sub- merged islands, which prove dangerous to bridges, jetties, &c. No satisfactory means of destroying the plant have as vet been devised. Some years ago certain rivers in Florida were completely choked up with this plant, which had been accidentally introduced. Specimens of the plant are at pre- sent growing in the Lily House, Kew Gardens. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. A Brazilian Linen Plant. The American Consul-General at Rio de Janeiro has re- cently sent an account to Washington of a plant which he considers likely to exercise an important influence upon the textile world in the near future. It has been described as Ganhamo braeiliensis, and is a common weed in Brazil, reaching a height of 12 to 18 feet within 12 month-. When carefully cultivated it matures within three months, and three crops can be produced in a year. The fibre has all the necessary qualities required for high-class use; strength, fineness,' flexibility, and adaptability lor bleaching, dyeing, &c. Everv part of the plant can be utilised for some indus- trial purpose, more especially fur the manufacture of writing paper. The cultivation was commenced with the assistance of the State Government, and is now said to have en from the experimental stage successfully, and its influence will be felt at once, the products of the plantations having been contracted for by British interests at a highly re- munerative rate. The production has been patented in the United States. The plant belongs to the Mallow family- Malvaceae, and although recently de-crib, d as a new species, prove-, to be the same a- the plant previously known as Hibiscus rail <\ Sir Samuel VVilks to the members of the Hampstead Scientific Society. Micro- scopic examination showed the sub-lance of the protuber- ance to consist of wood, the result of .111 outgrowth of " callus," which trees produce to heal wounds. In tin- pre- sent case probably a large branch was broken off, leaving a long wound deep in the centre of the tree and shelving off to the surface. This was the reason for the growth being one-sided, and for a large projecting boss of wood being formed as its foundation. CHEMICAL. By C. Ainsworth Mitchell, B.A. (Oxon.), F.I.C. Chrysalis Oil. The continual rise in the price of oils and fats has made it profitable to recover the oil contained in waste material, such as leather cuttings and wool waste, for manufacture into lubricants or soap, and experiments have been made to determine the value of other hitherto neglected sources of fat. Among the most recent of these may be men: Dr. Lewkowitsch's investigation ol the nature of the oil to be obtained from the chrysalis of the silkworm. The oil, after extraction by means of a suitable solvent, was dark brown in colour and bad an odour recalling that of fish oils. It could be clarified by filtration through fuller's earth, but on standing for some lime, threw down a floccu- lent deposit. Its specific gravity at 40" ('. was 0.9105, or practically the same as thai ol rod liver oil, which it also resembled in certain other physical and chemical charac- teristics. The proportion of oil yielded I > % the chrysalides was about 27 per cent., and although the dark colour would prevent its being used for the best soaps ii could probabl) be advanlageoush employed in lite manufacture of those ol a lower grade, Neon in Mineral Waters. Argon and helium are almost invariably present in the rare gases in natural mineral springs, and the researches of M. Moureu show that neon is also a frequent constituent. The method be has employed is that used b\ Sir James Dewar, which is based upon the power possessed b) nut charcoal of absorbing the ran gases with the exception of helium and neon, the spectra of both of which can then be identified in the residual mixture. By this means M. Moureu has found traces of neon in the gases from twenty- two mineral springs, and has also been able to identify helium in the gases from two springs in which it had not previously : ted. Alcohol from Peat. A few years ago the problem of obtaining fermentable sugar on a commercial scale from sawdust was successfully solved, and experiments on similar lines with peat as the raw material have recently given promising- results. It is well known that when starch is treated with a dilute acid ii i- converted into sugars and dextrins which can be more or less completely fermented by yeast, and a similar change can be effected, though less completely and with more diffi- culty by the action of acid upon cellulose, which forms a istituent of both sawdust and peal. The first at- tempts to manufacture alcohol from peat were marie in 187 1 by Herr '/.< tterlund, who seems to have obtained fairly successful results, but little more seems to have been done in ibis direction until 1905, when Herr Reynaud prepared a solution of sugar by heating peat with dilute sulphuric acid, and fermented this liquid by means of a yeast speci- allv cultivated for the purpose. These experiments were continued on a manufacturing scale during the early part ol last vear at Aalborg. and some thousands of gallons of spirit wire manufactured. Unfortunately, the liquid, after fermentation, did not contain more than 1 per cent, of alcohol, and it is qui whether the concentration of so weak a " wash " would pay. A somewhat richer yield of alcohol, however, seems to have been obtained in the ments indep ndently carried out last year by Herr I litis and Baron Fock, at Staatskosten. Ordinary peat containing about 62 per cent, of water was boiled for 15 minutes with dilute sulphuric acid in a closed copper v. --. ! under a pressure of three atmospheres, after which the ma-- was expressed under moderate pressure, and the filtrate neutralised with chalk and sepaiated from tl suiting gypsum. It was then fermented in large- tuns with .1 special yeast ami .< portion of the alcoholic product dis- tilled. The dijtillati contained <;£ per cent, of alcohol corre- sponding 10 a total calculated yield of 753 litres of absolute 1 from 225 kilos, of peai. A systematic study of the effect of varying the conditions as to the amount and con- centration of lb.- acid, the time of treatment and the pressure, will probably lead to a process which shall produce a stronger saccharine solution, and, consequently, a "wash" richer in alcohol. Assuming that this can be done, or that the cost of coni' -o weak a spirit is not loo great, a new industry might be started in Ireland, where the bogs woul I furnish an unlimited supply of the raw matt The Toxic Action of Rare Earths. The ran etals thorium, cerium, lanthanum, and ium are be-t known through their use in the manu- ol mantles foi incandescent gas burners. The chemical and physical characteristics of their salts have frequent!) been studied, but hitherto little has been known about their physiological action. M. Ileberl has. therefore, 1 series of experiments 10 discover the effect of the sulphates of the four metals upon animal and plant life, and various enzymes. He finds that guinea-pigs and frogs I bill little, if at all. by small doses of these sails, but that lisb are killed by being placed in water con- taining one part in 5,000. The toxic effect upon fish varies with the nature of the metal, zirconium being the most poisonou- and lanthanum the Ii 1st. Plants an- less sensi- tive than fish. They an- not affected until the concentra- tion of the soluti ies three pacts in 1,000, and do not Unions containing as much as live paiis In the case ol lower organisms, such as fungi and yeasts, and of enzymes, such as diastase and 1 Miulsin. the toxic effect of the sulphati mium and thorium is comparable with thai oi mercuric chloride. is the sulphati um and lamb. mum appear to \eii in relatively large amounts. Then -hip hi ivv .in the toxicity and the atomic weights of the rare-earth metals (viz., thorium, , cerium, 140; lanthanum, 138; and zirconium, for the poisonous action of tin- highest and lowest members of the scries is the most marked. 66 KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. GEOLOGICAL. By Edward A. Martin, F.G.S. The Geological Society of London. I'm prosperous ami flourishing condition of the Geological ol London is n matter of considerable public interest. i 1 the reporl ol the Council for 1906 we find thai the yn u closed with a total Fellowship oi 1,252. Hie Society will celebrate the centenary ol its founding in September next. This will be an interesting function, and ii is hoped thai man) delegates from kindred institutions al home and ibroad will attend. Mr. II. B. Woodward's Historj of the s ,cicty has now been completed, and the author is engaged in passing it through the press. The Wollaston Medal, the blue-ribbon of the geological world, has been awarded to sor \V. |. Sollas.F.R.S., the Murchison Medal has been awarded to Mr. Alfred Harker, F.R.S., and the Lyell Medal to Dr. I. !■'. Whiteaves, .1 sum of money accompanj ing the awards in the lasl two cases. No awards arc made this year from the Barlow-Jameson Fund, the Prestwich Trust Fund, and the Daniel-Pigeon Fund. The Council have exercised their powers very laudably in the allotment various funds, and it is believed there is greater deter- mination now to find oul workers in the provinces who have merited well of the science, and whose efforts sometimes languish for want of encouragement. It is hoped that the claims of the amateur geologist will receive full considera- tion, both in the mailer of awards, and in the recommenda- tions of the Council for seats on its own body. The Victoria Falls. The geology of the Zambesi Basin around the Batoka Gorge (Rhodesia) was the subject of an interesting paper read by Mr. G. W. Lamplugh, F.R.S., on January 23, at Burlington House. The author described in a most interest- ing and effective manner the portion of the river Zambesi as' it Hows through the great gorge, which forms the exit of the river after plunging down the Victoria Falls. Above the Falls the river has many channels, more or less shallow, and has here apparently reached the last stage of old age. The flow above is of a tranquil nature, and in times of drought great islands appear in the stream. Were it not for the fact that, just when it was approaching that stage when further excavation was almost impossible, and its waters were likely to spread over a wide area of basin, it found a weakness in its bed in the shape of transverse-fractured joint or series of joints, its rejuvenescence would not have been accomplished. Finding, however, this fracture filled up with easily-excavated material, it proceeded to denude it, with the result that after the lapse of long periods of time, the whole river now falls into the chasm. The exit of the river is not the full width of the chasm ; in fact, the exit is com- paratively narrow, and as this was presumably eroded where the process was easily done, it adds additional pro- bability to the theory thai the chasm of the fall was what may be called a rubble-filled fracture, easily disintegrated along its whole width. The width of the issuing stream as compared with the width of the falls is a phenomenon which may be satisfactorily thus accounted for. Mr. Lamplugh's vivid description of the geology of the neighbourhood was admirable in every way, and it was well illustrated by a well-chosen set of slides. But the subject is a great one, and he was careful to show in what direction future cx- plori rs may prosecute their researches. Earthquake Origins. It is unsafe to deny that volcanos and earthquakes have at times a real connection, although it may be that -some- times the one or the other may be alone noticeable. Earth- quakes may and do undoubtedly arise from explosions in volcanos, but many arise from other causes. The sudden formation of a fissure far underground, or the extension of a fault already in existence, may result in an earthquake, or even the collapse of the roofs of caves in a limestone district mav give rise to one. The results of numerous investiga- tions have showai that some of the most appalling catas- trophes have their origin at a very slight depth, as compared with the earth'- radius. Even the Charleston earthquake of 1886 had its origin bill about 12 miles below the surface, and probabl) the seal of origin in no case exceeds 20 miles. The outermost crust only seems to contain the yielding matei ial ; beyond it all is too compact to produce movement. The renl in the rocks which is thought to have caused the Charleston earthquake mad'' its effects felt from Boston to Cuba, and from Eastern Iowa to the Bermudas. The vibra- tions of a shock may be compared to the vibrations caused in air during the production of sound, such as when a sudden shoul is made. Each particle of the earth vibrates rapidly, the swing of each particle probably, as a rule, not exceeding a tenth of an inch, but the movement is there, and the shock ol this light movement of millions of particles, and their sudden arrestmenl and retrograde movement, are sufficient to cause the appalling results of a greal quake. Frequently after an earthquake land is found to have been raised, as, for instance, in iX_>.?, when the coast of Chile was suddenly raised three or four feet. Al other limes there is a sudden depression, as in 1 S 1 2 , when a region of 75 miles by 30 miles, resulted in the production of swamps and shallow- lakes in New Madrid, Mo. These phenomena must be rc- garded not as the effects of an earthquake, but rather as the visible effects of the disturbance lo which the' earthquake is due. Xoi necessarily, linn, an earthquake is caused by a connection with an outburst of volcanic energy, but as any shock to tin- crusl must result in a quake- of some sort, sec volcanic explosions may give rise to local earthquakes, although these mav not be felt many miles away from the volcano. On the other hand, the deeper that volcanic ex- plosion may occur, to the greater distance will the shocks be felt, and we cannot safely say from negative evidence alone, that volcanic action is not at work beneath our feet, resulting in quakings of the earth. ORNITHOLOGICAL. By W. P. Pycraft, A.L.S., F.Z.S., M.B.O.U., &c. Ailsa Craig. Considerable alarm has been created among bird lovers by the news that Ailsa Craig has been let by its owner, for a term of thirty years, for quarrying purposes on an exten- sive- scale. It is felt that this may have disastrous results in the bird colonies established there, partly on account of the blasting operations necessary for the dislodgment of the granite, and partly by the raids which will probably be made on the breeding birds by workmen and others. That such fears are not unfounded may be gathered from the fact that at the last meeting of the British Ornithologists' Club the matter was seriously discussed ; and, on the pro- pi esit ion of the lion. Waller Rothschild, it was at last decided to appoint a deputation of the Club to approach the Marquis of Ailsa, with a view to secure his interest in the matter, in the hope thai he may be induced to take all possible precautions to secure the birds from molestation. The Eggs of the Solitary Sandpiper. At the meeting of the British Ornithologists' Club held on January 16, Major 1". W. Proctor exhibited three sets of eggs of tin- Solitary Sandpiper (Totanus soli far ins) procured in Northern Alberta, N.-W. Canada, in June, 1903. These eggs excited considerable interest, inasmuch as they an- the first that have ever been brought to Europe. But, in addi- tion to their rarity, these eggs were remarkable on account of the light which they shed on the peculiar nesting habits of this bird. Thus, the first clutch contained live eggs taken from an old nest of the American Robin (Ttirdus migratorius). The second was incomplete, (wo e-i^gs only being found, and these in a nest of Brewer's Blackbird (Scolecophagus cyanoeephalus) placed in a tamarie tree five feet from the ground. The third was represented by three eggs also taken from a nest of the American Robin about 15 feet from the ground. The normal clutch appears to con- tain four eggs, which are laid in the deserted nests of other birds, and at some distance from the ground. Destruction of the Kite in Wales. We regret to have to draw the attention of our readers to the fact that a Common Kite has recently been killed near Brecon. In a letter to the Field (February q), Mr. Cam- March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. '/ bridge Phillips relates that he saw this bird in the flesh in the shop of a local gunmaker. It is to be hoped that steps will be taken to secure the conviction of the vandal who killed this bird, who should further be made to forfeit the specimen. Bitterns in Suffolk. The Rev. Julian Tuck, in the Zoologist for February, re- cords the fact that two Bitterns have recently been shot in Suffolk — one at Bardwell and one, a female, at Thorndon, near Eye. It seems a pity that these birds cannot be left alone, for they might yet be induced to breed here if given the opportunity. Sabine's Snipe in Ireland. Three samples of the melanic variety of the Common Snipe, known as Sabine's Snipe, were killed in Ireland during December, according to the Zoologist for February one near Ballina, Co. Mayo, on December 10, one in Co. Leitrim, December 15, and one in Co. Clare, December 20. The two latter appear to have been extremely good spei i- mens of this curious variety, lacking the characteristic stripes down the head and back. Snow Goose in Ireland. Mr. Robert Warren, in tin- Zoologist for February, gives some interesting particulars of a flock of Snow Gei 51 »eer by Captain Kirkwood on Bartragh Island, Killala Bay, on December 30. This Hock appears to have been composed of fourteen birds, four of which were a. lulls, as shown by the white plumage and black-tipped primaries. It is sUo-_ gested that these represented two broods accompanied bv the old birds. Snowy Owl in Ireland. Captain Kirkwood also reported having seen a Snowy Owl on a hillock anions' f'lc sand-hills in Bartragh, also on December 30. These birds appear to have been driven before the great snowstorm and three days' terrific northerly gale which ac- companied it. PHYSICAL. By Alfred W. Porter, B.Sc. Electrons and Radiation. Attempts have been made (e.g., by Nagaoka) to explain the existence of banded spectra and of series in line spectra in terms of the theory that the atom is built up of negative and positive charges of electricity. The electrons in such a theory are conceived as rotating, like planets, round a positive nucleus, which corresponds to the central sun. G. A. Schott, in the Philosophical Magazine, investigates the possibility of such a system being- the source of bands and series, and he comes, firstly, to the conclusion that a single ring cannot be made to account for them, and hence such a single ring cannot serve as the model of an atom. However, light can be thrown on the conditions which a true model must satisfy, by a study of such a system. Schott concludes from his investigations that radiation ol sufficient intensity and possessing the same range of wave- length as the observed lines in spectra, can consist of a number of waves too small to account for the lines even of one series if emitted l>v a single ring. Hence, he considers it useless to consider further the exact character of the system which will give rise to series of the same type as those of Banner, Rydberg, or Kayser and Runge. Acoustical Properties of Halls. M. Maragc has been studying several halls in Paris in regard to their acoustical properties. The result of the ex- periments is to confirm Sabine's theory. In any room an auditor hears three kinds of vibrations: til ["he primarj wave, which comes direct from the source; (2) diffuse waves, sent back bv tin- various surfaces in the room; (;) waves reflected regularly by particular surfaces, which give rise 1.. distini 1 ei hoes. In ordei thai a speaker ma) be distinctly heard there musi le no echo, and the diffuse sound must last lor a sufficiently short lime to strengthen the sound which gave rise ti> it, without encroaching on the nest. The duration of the diffuse sound can be expressed by the equation t — K/(a + b) where K is proportional to the volume of the hall, and a and 6 refer to the empty room and the spectators, respectively. As sources of sound, M. Marage has employed a vowel-siren, furnished with buccal resonators, in order to imitate the human voice as closelv as possible. As an example of his result-', we may cite that in the Salle du Trocadero, he finds that when empty, the duration of resonance is about 2 second-; when containing 4,500 auditors, it is reduced to 1' seconds. In this hall, in to be heard well, it is necessary to speak slowly, stopping bi Lwi 1 n each phrase. To keep down the disturbance from nice, one should not employ more energy in speaking than in the Physical Theatre at the Sorbonne, which only 250, and which has a remarkably short per' resonance (.6 second). The Joule-Thomson Effect. Reference has previously been made in these columns to ilie temperatures at which the heating (or cooling) of a gas in being forced through a porous plug (or throttle) may be expected to become zero. The only direct experimental determination of this inversion point had been made- by Olszewski in the case of hydrogen, and then for one initial pressure only. Examination of the necessary conseqi of van cler Waals' and other- characteristic equatio gases had led us to believe that a different inversion point would be found in general for every initial pressure. This published expectation has induced Olszewski to make direct determinations in the cases of air and nitrogen, with the result that the expectation is found to be fullv justified. For example, in the case of nitrogen for variations of the pressure on the high pressure side of the throttle, from about 160 atmos. to 30 atmos., the temperature at which no heat- ing or cooling took place varied continuously from 24 c C. to r.630 C For higher temperatures than the inversion one the gas became hotter in escaping, jusl as hydrogen d ordinary temperatures; for lower temperatures it cooled. The importance of this arises in part from the fact that a gas must be coeiled by other means below the in\ temperature before if can possil.lv begin to cool in any of the modern liquefying machines. Besides this reason, how- ever, there is the either important one, that additional light is hereby thrown upon the exact behaviour of gases, and we may hope that an extension of such experiments will ultimately lead to a more exact knowledge of the relations between the pressure, volume, and temperature of a gas, a relation which is expressed by the characteristic equation. ZOOLOGICAL. By R. Lydekker. Th^ Bcnte-Quasga. ONE of the larger South African mammals now verging on extinction, if, indeed, it has not already ceased to exist, is the typical race ot Burchell's zebra, the bonte-qu ... " pied quagga ") of the Boers, and the K^u typicus ol zoologists. This race- apparently inhabited the plains to the north of tin- Yuul River, now forming British Bechuanaland. It is charai b) the compli of barring on the legs and of strip, s on the lower part of the hind-quarters; while between the dark brown body- stripes were fainl "shadow-stripes" on the still paler ground-colour. The original specimen in the British Museum, brought home- by the gnat African traveller, Dr. Burchell, was, unfortunately, destroyed at a time when but little attention was paid to the priceless \ulue of "c and there is now no example of this race of th< the national collection. According, however, to ,1 paper published bj Mr. Ix. I. Pocock in the Annals and U of Natural History for 1897, there is. however, men in the museum at Tring. and .1 second in the Bristol Museum, both of which come ver) 1 lose to the typical form. 1 ;h neither is ex. utlv similar, and each -hll\ from the other. In these circumstances it is int. ■ learn thai 1 specimen exists in tic- An Museum of Natural History, which has recently I Mi. M. \Y. Lyon in the Hull, tin of that institu- tion. The specimen, which was purch 68 KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. Barn urn and Bailey's travelling menagerie in the year 1855, agrees very closely with the onv figured by Mr. Pocock. Peculiar British Mammals. At one time ii was considered that there were no mammals peculiar to the British Isles. The refinements of modern zoological methods are, however, gradually demonstrating tli.it the British representatives ol various species are, .-is might be expected, distinguishable from the Continental forms, and are, therefore, entitled to rank as separate races, although ii must be confessed that, in some cases at anj rate, their distinctive features are but slight. Some time ago, for instance, Prof. Einar Lonnberg, of I psala, pointed out thai Scotch red deer are distinguishable from the typical Swedish Cervun elaphus, and he according^ pro- posed that thej should !»• regarded as representing a race apart, under the name ol C. elaphus scoticus. More recently Dr. E. Satunin, of Xiflis, has called attention to the facl ili.il the British badger has a wider skull than the Con- tinental animal; and on this ground he has raised ii to the rank of a special local race, with the title Melts taxus britannica. Parasite and Host. Sea-cucumbers (holothurians) arc infested with certain small transparent fishes, which take up their abode in the body-cavitj of their host and live in luxury on the food brought within reach without any active exertion on their own part. Recently an American naturalist has had an opportunity of observing the manner in which the uninvited effects an entrance into his lodgings, "the fish, it seems, when it encounters a holothurian, feels its way with its head along the creature's side till it comes to the vent, into which it inserts the lip of its slender tail, and then gradually forces its way into the roomy interior. Three Interesting Mammals. The rare bush-dog (Speottos venaticus), of Guiana and Brazil, has long been the only known representative of its genus. A second species is. riv Ii) has, however, recently turned up in the Andes of Ecuador, and is remarkable for possessing a soft, woolly coat like that of an opossum, therebv differing altogether from any other known member of the dog- family. Another mammal which has hitherto been generally re- garded as the sole representative of its genus is the Chinese water-deer, Tlydropotes lor Hydrelaphus) inermis, charac- terised, in common with the musk-deer, by the absence of antlers in the bucks, whose upper jaw is, however, armed with long, sabre-like tusks. This animal inhabits the reed- beds ol the Yang-tse valley. Recently Dr. Max Hilzheimer, ol Strassburg, has described what he regards as a second species, under the name of II. kreyenbergi, from the neigh- bourhood of Hankow. It is chiefly, if not entirely, dis- tinguished by the characters of the skull. In the columns of the Field the present writer has contri- buted a note on certain North American moose-heads characterised by having the bald patch on the flabby muzzle T-shaped in place of triangular. He might have added that a Canadian specimen presented recently to the British Museum by Mr. Frank 1 1 Lit t shows the same peculiarity. The two specimens in which the feature is best displayed wi re reporti d to come from British Columbia, but this is now denied. The attention of sportsmen may be directed to the interest connected witli this feature. The papers read at the meeting of the Zoological Socictv on January 15 are mentioned in our last issue. REVIEWS OF BOOKS. New Catalogues. We have received catalogues — from Chas. Baker, of 244, High Holborn, of second-hand instruments of all descrip- tions, including microscopes, objectives, accessories, tele- scopes, physical and photographic apparatus, all excellent^ arranged ; from John YVheldon and Co., 38, Great Queen Stint, being the second and third parts of their excellent botanical catalogues, containing books on economic and geographical botany respectively; from E. George and Sons, 151, YVhitechapel Road, List Xo. 44, covering books on Natural History and kindred subjects ; and from YVm. Bryce, 54 and 54 V, Lothian Street, Edinburgh, containing books on chemistry, electricity, technology, &c. ASTRONOMY. A Century's Progress in Astronomy, by Hector Macpher- ■011, Junr. ; pp. xi. and J40 (Edinburgh: Blackwood, 1906; Os. net). To a certain extent this work resembles a simpli- fied edition of Miss ('hike's well-known work, to which the author acknowledges his obligation, an obligation which it will be difficult for any similar compiler for some time to come to avoid, lb- follows her in choosing Herschel as his Starting point, which, though .111 obvious thing to do, makes the "century" rather long. 'I he volume contains a fairly complete sketch of modern progress in most branches of astronomy, though geodetic work, for instance, is practi- Callv ignored. We do not like the persistent italicising of names, which is a feature of the book : nearly every man referred to, however unimportant, being provided with what are presumably intended to be lull and correct Christian names. The italics only serve to emphasize tin1 fairly obvi- ous fact that the names are nol invariably full or cornet. We may instance tin- names ol . Clive ; 2s.). — No better guide than this little book could be found by a student preparing for the Board of Education examination in the above subject. It is clearly written and well arranged, and each step is illustrated by simple experi- ments, most of which can be carried out without the help of the teacher. In fact, the learner is taught how to prove the truth of each statement, and to take nothing for granted. Many points frequently omitted in elementary bool chemistry are here dealt with in a way that must hold the attention. In the section on air pressure, for instance, the student is shown how to construct his own barometer, to make a chart of the daily readings, and to interpret the meaning of the figures. Diagrams and illustrations are supplied wherever necessary, and, in short, we can thoroughly recommend the book to anyone wishing to begin the study of chemistry. A Smaller Chemical Analysis, by G. S. Newth, F.I.C. ; pp. v. and 147 (London : Longmans, Green, and Co. ; 2S.). — The name of Mr. Newth is deservedly so well known in connection with the teaching of chemistry that we know beforehand that any book on the subject written by him will stand the test of practical work. This is certainly true of this book, which is practically a condensation of the qualita- tive section of the author's Manual of Chemical An- The directions are so clear and sufficient, though without loss of conciseness, that they can easily be followed bv a student working by himself". The scope of the book is essentially the qualitative analysis of simple s.Jts, though the last chapter gives a description of a few of the more simple volumetric methods of quantitative anal; PHOTOGRAPHY. Lantern Slide Making and Exhibiting, by [ohn A. Hodges, F.R.P.S. (London: Marshall, Brookes, and Chalkley, Ltd.; [aire 6d. net.). — This small volume of 37 of reading matter, and a few illustrations is I Of the Focus Photographic Manuals. The beginner will find it a reliable and useful guide, and will probably regrel ih.il (he author has not given him still more of his ex- periences, MISCELLANEOUS. 1 hi Febi an \ number of the .'/ tains, like its predecessors, a large amount of varied and mis- OUS information on natural history and other suh- icale of Lepisma saccharina with the radial markings uppermost, and Fig. 5 one with the longitudinal markings upper- most, whilst Fig. 6 shows the obliteration of the latter by a grease spot on that side. Fig. 7 illustrates Mr. McGhie's suggestions as to the evolution of insect hairs and scales. Collecting: Algae. In a French scientific journal, M. Gomont gives some instructions to travellers on methods of preparing alga; for an herbarium or for examination. He divides the algae into two groups, those which are visible to the naked eye, and those which are microscopic- in size, and advises the careful labelling of each specimen, with its locality, and the nature of its habitat, as a matter of routine. The whole plant shotdd 1:;- gathered, including its base. Some may be hung on a line in the shade to dry, but more delicate specimens should be laid out on a piece of sized paper, covered with calico, and pr< between sheets of blotting paper, both calico and blot- ting paper being frequently changed to ensure speedy drying. "When the specimens are dry. the calico is removed, and the sheets packed on each other; or the specimens can be floated in sea-w ater. and a piece of paper inserted underneath, when they can then lx> teased out and left on an inclined plane to drain. A solution containing 35 to 40 grammes of salt per litre of water will do if sea-water is not available. Salt may also be used as a preservative, the specimens, after draining, should be packed, in alternate layers of algae and salt, in a stone jar, and the vessel sealed. This method is suitable for a short journey only. For microscopic alga-, quick drying in the open air on a sheet of sized paper is host, without calico or pressure. Diatoms and desmids may he placed in a drop of water and allowed to dry naturally. The author discourages the use of liquids for preservation of algae, except for portions of plants which are to be studied anatomically, for which he recommends 90 per cent, alcohol, to which he adds a certain quantity of glycerine or a solution of picric acid. Mounting: Mosses. In the Bryologist, Mr. J. I-'. Collins sixes some hints on the mounting of mosses lor the herbarium. Instead of the usual method of pinning the envelopes or pockets to the sheet. In- uses half-inch discs of paper, gummed on both sides, to attach the envelopes, a single wafer being sufficient to hold most envelopes firmly, and being readily detached by a paper-knife. To mount specimens direct upon the sheet, he uses commercial liquid glue, diluted with an equal quantity o\ vinegar or water, which is brushed in a thin layer upon a shex t of glass. Ilk- specimen is rapidly pressed upon this and trans- ferred to its position on the herbarium sheet Small mens, mounted with a certain amount of soil at- tache.I, which gives trouble by crumbling away, are easily hardened by a few diops of diluted white shellac- one part of shellac to three parts of 95 per cent, alcohol. nmications and inquiries ."i Microscopical nut! addrtsstd to '•'. Skill ' <. " Jersey,' St. Baruabis Cambridge. Correspondents an request, ;i spe;:m'ns to be nam, 72 KNOWLEDGE & SCIENTIFIC NEWS. [Maki ii, 1907. The Face of the Sky for March. r>y W. Shackleton, F.R.A.S. The Sun. — On the 1st the Sun rises at 6.50 and sets at 5.37; on the 31st he rises at 5.42 and sets at 6.28. The Sun enters the sign of Aries at 7 p.m. on the 21st, when Spring comment es. The Solar disc has been fairly well marked with Sun- spots of late. At the time of writing there are two conspicuous spots visible. The position of the Sun's axis, equator, and belio graphic longitude of the centre of the disc is shown in the following table : — ivii, Axis inclined from N. point. Centre of disc S. of Suns Equator. Heliographic Longitude of Centre of Disc. Mar. 2 7 ■• 12 .. 17 •• ,, 22 ,, 27 .. 49'W 59'W -3° 59'W 24° 50 'W 25° 29 'W 25 59'W 7° 14' 7° 15' 7° 13' 7° 7' 6° 58' 6° 46' 67° 51' 1° 58' 296° 5' 230° 1 1 ' 164° 16' 98° 20' The Zodiacal light should be looked for in the west for a few hours after sunset. The Moon : — Date. Phases. H. M. Mar. 7 .. ,, 14 .. ,, 22 . . ,, 29 .. d Last Quarter • New Moon 5 First Quarter O Full Moon 8 42 an, 6 5 a.m. 1 10 a m. 7 44 P-m. Occultations. — The following are the cccultations of the brighter stars visible at Greenwich : — Star's Disappearance. Reappearance. Moon's Name. M Angle Angle Age. s Mean from N Mean from N. Time. point. Time. point. p. m. p. 111. d. h. Mar. 20 m Tauri . . Vi 9 24 1230 10 17 228° 6 iG ,, 21 X1 Ononis t'7 7 16 a. m. C40 8 30 a. m. 290° 7 14 ,, 22 X4 Ononis 4'8 O 30 95° 1 25 268° 7 19 p. m. p. m. ,. 3° 80 Virginis 5'8 7 42 1800 8 4 227 16 14 The Planets. — Mercury (Mar. 1, R.A. 23h 50™ < Dec. N.o°3i'; Mar. 31, K.A. 23" i8°>; Dec. S. 40 4') is an evening star in Pisces during the early part of the month. On the 2nd the planet is at greatest elongation of 180 9' E. from the Sun, when he sets at 7.26 p.m., or if hours after the Sun. Hence, about this date, he is favourably placed for observation immediately after sunset. The planet is in inferior conjunction with the Sun on the 18th. Venus (Mar. 1, R.A. igh 42™ ; Dec. S. 190 24'; Mar. 31, R.A. 22'' 2"'; Dec. S. 120 22') is a morning star in Capricornus, rising at 4.50 a.m. on the 1st and 4.30 a.m. on the 31st. The telescopic appearance of the planet is gibbous, -7 of the disc being illuminated. Mars (Mar. 1, R.A. i6h50m; Dec. S. 2i°56'; Mar. 31, R.A. i7h57m; Dec. S. 230 30') is a morning star in Ophiuchus, rising at 2 a m. on the 15th. The planet is getting within range of ordinary telescopes, the apparent diameter of the disc being 8". Jupiter (Mar. 1, R.A. 6" 4™ ; Dec. N. 23029'; Mar. 31, R.A. 6n i2m; Dec. N. 230 31') is describing a short direct path about 1° North of the star ij Geminorum. I In planet is very conspicuous, and is due South about 6.30 p.m. near the middle of the month. The equatorial diameter on the 15th is 39", whilst the Polar diameter is 2"'5 smaller. The following table gives the satellite phenomena observable before midnight : — to a in c 0 c OJ E 0 a ja B. P.M.'s H. M. Q a 0 a -a a. PM.'s. H. M. Mar Mar Mar 1 1. Oc. D. 6 1 1 Q I. Sh. E, 9 24 21 I. Tr. I. 9 38 1. EC. I). 10 12 11. Ec. R. 10 19 11. Oc. D. 10 6 2 I. Sh. E. 7 29 III. Ec. R. II 56 I. Sh. I. 10 56 II. Ec. R. 7 44 15 1\\ Oc. R. 7 13 III. Oc. D. 11 36 III. Ec. R. 7 54 1. Oc. D. 10 31 I. Tr. E. 11 55 7 IV. Sh. I. 8 29 16 11. Oc. D. 7 33 24 I. Ec. R. 10 28 II. Tr. I. 10 20 III. Oc. D. 7 38 25 II. Sh. I. 7 3° IV. Sh. E. 11 9 I. Tr. I. 7 44 II. Tr. E. 7 42 I. Tr. I. 11 22 I. Sh. I. 9 I I. Sh. E. 7 43 8 I. Oc. D. 8 37 I. Tr. E. 10 I II. Sh. E. 10 23 9 III. Oc. R. 6 48 III. Oc. R. 10 42 27 III. Sh. E. 10 11 I. Sh. I. 7 6 I. Sh. E. II 19 30 I. Tr. I. 11 33 1. Tr. E. 8 8 17 I. Ec. R. 8 33 I' I. Oc. D. 8 50 III. Ec. D. 8 53 18 II. Sh. E. 7 45 " Oc. D." denotes the disappearance of the Satellite behind the disc, and " Oc. R." its reappearance; " Tr. I." the ingress of a transit across the disc, and " Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc, and " Sh. E." its egress ; " Ec. D." denotes disappearance of Satellite by Eclipse, and 'Ec. R." its reappearance. Saturn (Mar. 1, R.A. 2311 14""; Dec. S. 6° 57'; Mar. 31, R.A. 23I1 28m ; Dec. S. 50 33') is in con- junction with the Sun on the 9th, and hence is unobservable. Uranus (Mar. 15, R.A. i8h 53™ ; Dec. S. 230 13') is a morning star in Sagittarius, rising about 3 a.m. Neptune (Mar. 15, R.A. 6h 43™ ; Dec. N. 220 13') is situated in Gemini about 30 South of the star e Gemin- orum. The planet is difficult to identify among the numerous small stars appearing in the same field of view, but can be detected by his motion if observa- tions are made some nights apart. Meteor Showers : — Date. Radiant. Near to Characteristics. R A. Dec. Mar. 1-4 . . 14 •• „ 24 •• h. m. ii 4 16 40 10 44 + 4° + 54° + 58° t Leonis fj. Draconis p Ursa? Maj. Slow ; bright. S«ift. Swift. Minima of Algol occur on the 1st at 11.46 p.m., on the 4th at 8.34 p.m., and the 24th at 10.17 p.m. Double Stars. — 7 Leonis, X.'1 14"', N. 20° 22', mags. 2,4; separation 3"-6. The brighter component is of a bright orange tint, whilst the fainter is more yellow. 1 Leonis, XI." 19™, N. n° 5', mags. 4^, -jh; separa- tion 2''-4. This object requires a favourable night and a fairly high power on small telescopes. a Canum Venat, (Cor Coroli), XII.h 52™, N. 380 49', mags. 2-5, 6-5, separation 20"; easy double, can be seen with moderately low powers, even in 2-in. telescopes. Cluster. — M 44, the Praesepe in Cancer, visible to the naked eye as a nebulous patch, best seen and easily resolvable with a pair of opera or field glasses. Situated about midway and a little to the west of the line joining « and 5 Cancri. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. vi 1. THE BAUSCH & LOMB world-famed MICROSCOPES & ACCESSORIES Stands For all classes of work, from 38/6 to £50. (See Complete Catalogue.) Objectives. Stand"B.H." From £5. 5. With 2I3 & 1/6 Objectives, at » Eye- piece. 2 srds Dry. 15/= i/i2th Oil Imui. 100/- i/6th Dry. 30/= i/i6th Oil Imm. 160/- Corrected for 160 m/m Tube Length. {See Complete Catalogue.) Centrifuges. Single and Double Speed, Water and Electric power. [Separate llluttrattd Liit Pott Free ) Microtomes of all Grades, from the simp'est (yet practical and eftectiv-) at 20/- (Separate Illustrated Lilt post free 3d.) ■B ill g Photographic Lenses, jj{ A SIMPLE TREATISE. j*j By CONRAD BECK and HERBERT ANDREWS. Ttl ■S ft 9 i 1/-, Post Free 1/3. This book contains 323 pages. It is written in a popular style ; no knowledge of mathematics is required. Nearly 15,000 have been sold. It gives the infor- mation which t-he photographer requires, and in a simple manner. Section Section COMPLETE ILLUSTRATED MICROSCOPICAL CATALOGUE (84 pp.), 3 Stamps to cover postage, from ths Sole Repbesentatives of Bausch & Lomb Optical Co., for U.K. and Colonies. A. E. STALEY & Co., Contractors to the British, Indian, and Colonial Governments. Principal Hospitals, Colleges, and Schools of Bacteriology. 19, Thavies Inn, Holborn Circus, LONDON, E.C. U'i B 1 H Section III. Section IV. Section V. Section VI. Section VII Appendix I Appendix I CONTENTS. -FUNCTION OFTHE PHOTOGRAPHIC LENS. -GLASS AND THE MANUFACTURE OF LENSES. -CORRECTIONS. -PROPERTIES OF LENSES. -TYPES OF PHOTOGRAPHIC LENSES. -PRACTICAL APPLICATION FOR DIFFER- ENT CLASSES OF WORK. —LENSES FOR SPECIAL PURPOSES. -EQUIVALENT PLANES. .—LENS TESTING. CATALOGUE OF APPAHATVS. R. & J. BECK, Ltd., 68, GORNHILL, LONDON. Practical Notes on Telephotography. FREE ON APPLICATION TO R. & J. BECK, Ltd.. 68. Cornhill. London. ■■rJS«MrJ5«Mrj:»v-tri:»v-*ri:»v. MICROSCOPISTS. Do you use GIFFORDS F LINE or any other Screen ? If so, the WRATTEN VERICHROME will reduce your exposures enormously. SPECIAL BOOKLET READY SHORTLY. Wratten & Wainwright, LP CROYDON. IMPROVED FORM OF DIRECT VISION SPECTROSCOPE, With PHOTOGRAPHIC SCALE and MIRROR for ILLUMINATION In Morocco Case £3 10 0 LISTS ON APPLICATION. ADAM HILGER, Ltd., 75a, Camden Rd., London, N.W. Awarded Gold Medal St. Louis Exhibition, 1004. Telegrams : " Sphericity London." Telephone : 1687 North. NOW READY. A MOST ACCEPTABLE GIFT AT ANY TIME. 6R> KNOWLEDGE And ILLUSTRATED SCIENTIFIC NEWS VOLUME FOR 1906. OVER 300 PAGES AND 200 ILLUSTRATIONS, many being Full Page Plates. Bound in Blue Cloth, Gilt Design and Lettering, 8s. 6d. net. Post Free within the United Kingdom. PUBLISHING! OFFICE: 27. CHANCERY LANE, LONDON. Vlll. KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. POPULAR ASTRONOMY. NINE VOLUMES COMPLETED. A Reference Work on Current Astronomy. Over 500 Pages of Reading Matter Fully Illustrated in each Volume. Containing the Latest Astronomical News. Articles on Astronomical Themes. Many Fine Engravings. Spectro- scopic Planet and Comet Notes. Star Charts every Month. A Valuable Work in any General Library. The tenth Volumo (of ten numbers) will be sont in pamphlet form to any address in the United States or Canada on receipt of 2 dollars 50 cents. Foreign price, three dollars. Preceding volumes at same prioe. G00D8ELL OBSERVATORY OF CARLETON COLLEGE, NORTHFIELD, MINN., U.S.A. WILLIAM W. PAYNE. H. C. WILSON. Sole European Agents : — WILLIAM WESLEY & SON, 28, Essex Street, Strand, London. JUST ISSUED. THRICE-GREATEST HERMES Studies in Hellenistic Theosophy and Gnosis. Being a Translation of the Extant Sermons and Fragments of the Trismegistic Literature, with Prolegomena, Commentaries, and Notes. By G. R. S. MEAD, B.A., M.R.A.S. VOL. I.— PROLEGOMENA. VOL. II.— SERMONS. VOL. III.— EXCERPTS AND FRAGMENTS. Large Svo, Cloth, 307- net. THE THEOSOPHIGAL PUBLISHING SOCIETY, 161, NEW BOND STREET, W., AND ALL BOOKSELLERS. PRICE TWOPENCE MONTHLY. Illustrated. The Cheapest Natural History Magazine. NATURE NOTES. The Magazine of the SELBORNE SOCIETY. With which is Incorporated "THE FIELD CLUB." Edited by G. S. BOULGER, F.L.S., F.G.S- Professor of Botany and Geology, City of London College. Specimen Copy forwarded on receipt of Two Penny Stamps. JOHN BALE, SONS, & DANIELSSON, LTD., GT. TITCHFIELD ST., LONDON, BINDING". We are pleased to Bind Readers' Parts of "KNOWLEDGE." In Dark Blue Cloth Case (Special Gilt Design and Lettering), with Index, at 2/9 inclusive per Yearly Volume. POSTAGE SIXPENCE EXTRA. Also in more expensive forms, wJiere desired, at moderate ekarges. KNOWLEDGE" OFFICE, 27, CHANCERY LANE, LONDON. BIRKBECK BANK Established lwl. SOUTHAMPTON BUILDINGS. HIGH HOLBORN, W.C. 2* PER CENT. INTEREST allowed on Deposit Accounts. 2 PER CENT. INTEREST on Drawing Accounts with Cheque Book. All general Banking Business transacted. ALMANACK with full particulars, POST FREE. C. F. RAVENSCROFT, Secretary F. WIGGINS & SONS, 102 & 103* MINORIES, LONDON, E Contractors to H .11. ^^^^M i OB Government. ^-^B V^B INDEX. %Vi5^^r^vEPi; The Index for covering the issues JANUARY TO DECEMBER, 1906, IS NOW READY. ELECTRICAL WORK, AND Ait, PURPOSES. Largest Stock in the World. Tel. No. 2248 Avenue. Price THREEPENCE net. Post Free. Advertisement Rates. ADVERTISERS NOTE. £ s. d. Whole Page .... 6 6 O Quarter Page - - - - 1 15 O One-Eighth Page - - - O 18 6 ^ One-Sixteenth Page - - O 10 O Extract from a letter received. Bournemouth, February 6th 1906. " I have subscribed to Knowledge for many years. My home is in South Africa. I am on a visit to the old country. I may say that in South Africa I look forward with eagerness to the post that brings me Knowledge,. You may be surprised to know that the first things I Per Inch, Narrow Column - O 7 O J read are the advertisements. I go through them all carefully as a matter of education, and to keep me in touch with the newest and best of things, and to help me get what I want. I have often been able to purchase things of great use to me of which I should have known nothing but for the advertisement in Knowledge." Discounts for series of insertions and Rates for Special Positions, when vacant, on application to the Advertisement Manager, KNOWLEDGE & SCIENTIFIC JEWS OFFICE, 27, CHANCERY LANE, LONDON, W.C. THE renew th ADVERTISERS THEMSELVES (be ing their advertisement orders) frequently exp eir satisfaction with Knowledge as a meJiur yond ress n. March, 1907.] KNOWLEDGE & SCIENTIFIC NEWS. IX. LONDON AND COUNTY BANKING COMPANY LIMITED. Registered under "The Companies Acts." Established in 1836. CftPITAt £8,000,000, in 100,000 Shares of £8 0 each. REPORT adopted at the Half- Yearly Ordinary General Meeting, the 7th February, 1907. CHARLES JOHN HEQAN, Esq., in the Chair. The Directors in submitting to the Shareholders the Balance-sheet for the half-year ending 31st December last, have to report that after paying interest to Customers and all charges, making provision for bad and doubtful debts, and allowing £43.106 6s. 5d tor rebate on bills not due, the net profits amount to £325.006 is. tod. From this sum have been deducted £50,000 allocated <° ™"ng down the Bank's holdings in Corporat.on Stocks. £25,000 transferred to Premises Account, and £50000 carried to Resene Fund (raising it to £1,550,000), leaving £200,006 is. iod., which, with £97.365 2S. lod. Dalance brought forward from last account, leaV6S ^Th^Directors^have dedarecTa Dividend for the half-year of 10 per cent., which will require £200,000, leaving the sum of £97,371 4s. 8d. to be carried to the Profit and Loss New Account. The present dividend added to that paid to 30th June will make >o per cent^ ^.^^"'J^ deep regret, announce the retirement from the Board of William Howard, Esq., who entered the service of the Bank in 1862, and who has been for the past ten years a most valuable member of their body. The Directors retiring by rotation are William McKewan, Esq., Oswald Cecil Magmac, Esq , and Charles James Cater Scott, Esq., who, being eligible, offer themselves for re-election. • The Dividend" £2 per Share, free of Income Tax, will be payable at the Head Office, or at any of the Branches, on or after Monday, 18th February. — ==— ^— — — ^==^==^==^^= gr. BALANCE-SHEET of the London and County Banking Company Limited, 31st December. 1906. ffr. To Capital subscribed £8,000,000 £ s. d. £ s. d. Paidup 2,000,000 0 0 ReserveFund 1,550,000 0 0 Due by the Bank on Current, Deposit, and other Accounts, including provision for Contingencies 44.990,316 12 9 Liabilities on Acceptances, covered by Cash, or Securities or Bankers' Guarantees 2,722,692 2 10 Rebate on Bills not due carried to next Account 43,106 6 5 Net Profit tor the Half-Year, after making provision for Bad and Doubtful Debts .... 325,006 1 10 Transferred to Investment Accounts 50,000 0 0 275,006 1 10 Transferred to Premises Account 25,000 0 0 250,006 1 10 Carried to Reserve Fund 50,000 0 0 200,006 1 10 Profit and Loss Balance brought from last A" _97L»5_L10 4 g £51,603,486 6 8 £ s. d. By Cash at the Head Office and Branches, and with Bank of England 8,093,142 9 Loans at Call and at Short Notice 3.301,623 Investments, viz. : — Consols registered and in Certificates (at 85), New 21 per Cents., and National War Loan "(£6,S94,491 7s. lid., of which £357,000 0s. Od. Consols is lodged for Publio Accounts) ; Canada 4 per Cent. Bonds, and Egyptian 3 per Cent. Bonds, Guaranteed by the British Government 6,654,438 16 1 India Government Stock and India Govern- ment Guaranteed Railway Stocks and Debentures 898,981 16 10 Metropolitan and other Corporation Stocks, Debenture Bonds, English Railway De- benture 8tocks and Colonial Stocks 1,64 1,109 IS Other Securities 19.586 17 9 Discounted Bills Current 7,628,467 3 0 Advances to Customers at the Head Office andBranchas 19,885,994 8 Liabilities of Customers for Drafts accepted by the Bank (as per Contra) Bank Premises in London and Country, with Fixtures and Fittings 829,446 13 11 Lem amount transferred from Pi -.Hit an. 1 1. 1 ! ,00J 0 0 s. d. 11,394,765 11 9 9,217,120 6 5 27 464,461 11 9 J 2 10 B04.446 13 11 £51,603,486 6 8 PROFIT AND LOSS ACCOUNT. £ e. d. To Interest paid to Customers 231,273 2 1 Salaries and all other Expenses at Head Office and Branches, including Income Tax on Profits and Salaries, Auditors' and Directors' Remuneration ■ 331,311 1 1 0 Transferred to Investment Accounts 50,000 0 0 Transferred to the Credit of Premises Account 25,000 0 0 Carried to Reserve Fund 60,000 0 0 Rebate on Bills not due, carried to New Account 43,106 6 5 Dividend 10 per cent, for the Half-Year £200,000 0 0 Balance carried forward 97,371 4 8 297,371 4 B £1,028,065 4 2 By Balance brought forward from last Account Gross Profit for the Halt- Year, after making Provision for and Doubtful Debts, and including Reb.t:. brought from 30th June last Bad -1., s. a, J 10 930.700 1 1 £1,038,086 1 I Examined and Audited by us, Audit Committee of Directors, (Signed) J. J. CATER, E. H. CUNARD, W. E. HUBBARD, H. R. WYATT, Head Office Manager. W. G. GRIBBLE, Country Manager. T. J. CARPENTER, Chief Accountant, London and County Banking Company Limited, lltli January, 1907. In accordance with the provisions of the Companies Aot, 1900, we certify that all our requirements as Auditors have bean compiled with, and wo report that we have examined the Balance-sheet and Profit and Loss Account, dated the . 1906, h.ive vended the Cash- Balance at the Bank of England, the Slocks there registered, and the other invest- ments of the Bank. We have also examined the several Books and Vououers and certified U-turns showing the Cash-Balances, Bull and other Amounts set forth, the whole of which are correctly stated ; and in our opinion the said Ualance-shnet and Profit and Loss Account are properly drawn up, so as to exhibit a true and correct view of the Company's affairs as shown by the books of the Company. Jompany t (Signed) 11 V. GRANT, THOS. HORWOOD, STUART PI.EYDELL-HOUVERIE, AuMtori. LONI'ON AND COCNTT BANKING COMPANY LIMITED, 17fn Jiinunry, 1907. KNOWLEDGE & SCIENTIFIC NEWS. [March, 1907. FOR SALE.— To Close Estate. First-class BINOCULAR MICROSCOPE, bv Bi 1 k,mi chanicalstagewithconcentricmotionbyracfc an. I pinion, scp.ir.itr Moiioculu body with divided drawtube, Substage with rack and pinion focussing andcentringadjustments, Achromatic condenser with iris diaphragm, 2 silver side reflectors, Camera lucida, erector, and various other pieces of appara- tus. The whole contained in handsome Spanish mahogany case, £40 0 0. Cost £82 10 0. MONOCULAR MICROSCOPE, by Watson l" Pram ">, has mechanical stage, centring substage with rack pinion and screw. The whole in new con- dition in mahogany case, price £6 10 0. Cost £8 6 0. TABLE SPECTROSCOPE, by Browning, 8 prisms, rack tube and collimator, scarcely used. In mahogany case, £10 0 0. Cost £15 0 0. Can be ten h}i Appointment or any Particular* of Executor*. 199, South Lambeth Road, London, S W. FOR SALE — Second- Hand . Microscope Slides, 6/- dozen. Mahogany Cabinet, for i.ooo, £3 15s. Bacteriological Microscope, Spencer (New York) in- eluding ,V. oil immersion, £10 ISs. ; bargain. Beck Medical Student's Microscope, '\ and J by Zeiss (A. & D.)i £4 18s. 6d. Watson's Edinburgh Microscope, I in. & *, in., £5 5s. Calver's ttiin. Reflecting Telescope, nearly new, with slow ii m ■! m >ie., £15. 5 in. genuine old Wray, with Stand, £45. Equatorial, Cooke's best pattern, for 3 in. to 4 in. (Offers.) Many others— all kinds and makers. Clarkson's Second-Hand Optical Hart, 338, High Holborn, London (opposite Gray's Inn lt apotogiu to the ituimtBvimct of Mtnrnmt/h A. BOURNE & CO., The London Engravers. Copper. Half Tone. Line Zinco, Woodcuts. SCIENTIFIC AM) NATURAL HISTORY SUBJECTS A SPECIALITY. Vofcen of r'tr Block* ttftil in thi) Journal, 73 ludg^vte HILL, E.C Telephone: 3(03 Central. MERCURY VAPOUR LAMPS in ordinary or UVIOL Glass, are now extensively used in the (JENA MAKE), r UVIOL Glass, are no Leading Laboratories in this country and abroad. All Sizes from 10 ins. to 40 ins. We supply these LAMPS UNMOUNTED with the necessary SELF INDUCTIONS and RHEOSTATS. Also a SPECIAL LABORATORY TYPE. Sole Agents for U.K. and Colonies— ISENTHAL & CO., 85, MORTIMER ST., LONDON, W. Contractors to Die Admiralty, War, India, and Colonial Offices, dc. Ask your GROCER for TO-DAY'S Leading Lines. |J W^ ^N DELICIOUS FOR BREAKFAST riblL/| <* AFTER DINNER. WHITE COFFEE. & BLUE In making, me less quantity. It being much itrongar than ordinary Coffee ENGLAND'S BEST VALUE! "BONGOLA" TEA Has No Equal. EXCELSIOR SARDINES DOUBLE CROWN * * SALMON & LOBSTER. In flat ft tall tins, paeked from the finest selected Fish only, ft cannot be surpassed. Perfect Flavour. .Selected from the Finest Fruit. EXCELSIOR CANNED GOODS PEACHES, APRICOTS, PEARS. GREENGAGES PEATMOOR OLD Scotch WHISKY. "Soft. Mellow, Delightful. Carries the Wild Rough Scent of the Highland Breeze." A NEW PATTERN } FORTINS STANDARD BAROMETER (Registered Design No. 420,297.1 As will be seen by the illustration, tbiB Barometer is built on original lines. By the absence of the ordinary tubular enclosures (in the usual form of instrument) the mercurial column is FULLY EXPOSED to view, NO SHADOWS are thrown upon the column, and therefore an extremelv accurate and instan- taneous reading is made possible. The scales being gradu- ated upon tbo flat side pieces the DIVISIONS AND FIOURES ARE ALWAYS IN VIEW, and the vernier is very much more legible than in the ordinary tubular patterns. The bore of the tube is O'S Inch. The scales are graduated io incheBand millimetres, and, by means of the verniers, are capable of being sub-divided to read to 0-002 Inch and 0-l m/m. The attached Thermomete r on the body of the instrument is graduated in Fahrenheit and Centigrade scales. It is the BOLDEST Standard Barometer made. The PRICE IS LOWER than that of any other form of Standard Barometer of the same dimensions. It yields readings equally close as the highest priced instruments. Price complete, mounted on handsome Polished Solid Mahogany Board, with Brackets for Suspension, and Opal Glass Reflectors, £7 lOs. Od. SMALLER SIZE, "THE STUDENTS," designed for Schools for demonstration work, and small private Obsenatonts; bore -25; reading to *01 inch and ■1 millimetre. dB3 7s. 6d. Sole Makers cend Ptoprietors of the Registered Design: PA8T0RELLI & RAPKIN, Ltd., '/ .;// kinds o_f Meteorological ItistrumenU. GARDEN, LONDON, E.G. Actual Mamtfactwrt 46, H ATT ON EBtabliahed 17.">0. Contractor) to H.M. Gori*rnm< Tel phone No. 1081, Holborn. Telegrams— " Rapkin, London." STANDARD INSTRUMENTS OF ALL KINDS (With Kew Certificates if desired). ILLUSTRATED .PRICE LIST POST FREE. Wireless Telegraphy IMPROVED APPARATUS (READY SHORTLY) enabling amateurs to receive TUNED or SYNTONISED Wireless Messages from all existing Stations. The apparatus is capable of receiving over a range of 300 MILES with an aerial elevation of only 50 feet. Prices and full particulars on application to the SOLE MANUFACTURERS— HARRY W. COX, ltd., MANUFACTURING ELECTRICIANS, Contractors to many Departments of H.M. Govt., la, ROSEBERY AYENUE, & 15-21, LAYSTALL ST., LONDON, E.C. PrinteJ and Published lor the Proprietors by Kiso, Sell i £ Oldino, Ltd., 27, Chancery Lane, London, W.C.— March. 1907.