APPS, 433 STRAND, LONDON. MANUFACTURER of Patented Induction Coils, other Scientific Instruments and Engineering Appliances to the Government Departments. JOINTLESS SECTION COILS, my system of 1868, to order, to in. Coils 4000 ohms R, very thick discharge. Primary Coils for 10 to 230 volts. COMMERCIAL SERIES OF COILS, as Fig., at about one-half of cata. logue prices. Maker and Designer of the following Coils :- THE SOUTH KENSINGTON COIL, 48 in. spark. Special Coils for NEW TRIPLE-POLE MERCURY BREAK, giving a stream-like effect when used with Apps' Patented Induction Coil (this can be fitted to any Induction Coil), £6 6s. HOSPITAL X-RAY SETS, complete in every detail, from £25 each. The Model Apparatus adopted for South Africa, with Batteries, small Steam Motor, &c. SETS OF X-RAY APPARATUS suitable for Field Hospitals, from £50. HIGH FREQUENCY APPARATUS of my newest models. DECEMBER. NINEPENCE NET. PROGRESS OF SCIENCE AND TECHNOLOGY. THE DETERMINATION OF ATOMIC MASSES. By MORRIS W. 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Patent Lantern (Stroud and Rendall's and Kershaw Patents), made of best seasoned mahogany, French polished, lined with asbestos and Russian iron. Fitted with two double achromatic objectives, 90° silvered prism, complete with B.T. or mixed jet, in travelling case, measuring 23" X 16" X 9". ALL ACCESSORIES SUPPLIED. ARC LAMPS, RESISTANCES, MAKER STANDS, &c. A. KERSHAW, Dorrington St., Leeds. CONTRACTOR TO H.M.'s GOVERNMENT. FLUORESCENT MINERAL TUBES, showing the beautiful effect produced by Willemite and other minerals, under the Cathode Rays. 15/- EACH. List of Minerals and colours produced on application. Also Pitchblende & Radio-active Salts. A. C. COSSOR, 54 Farringdon Road, London, E.C. AWARDED GOLD MEDAL, ST. LOUIS EXHIBITION, 1904. Telephone-10547 Central. For Photography, Unsurpassed for fine definition. COOKE LENSES TAYLOR TAYLOR HOBSON IT STOUGHTON STREET WOD AND 10 Degree LEICESTER. LONDON W THE IRISH NATURALIST. A Monthly Magazine of Irish Zoology, Botany, and Edited by GEO. H. CARPENTER, B.Sc., and R. LLOYD Annual Subscription, 5s. Post Free to any Address. Dublin: EASON & SON, LTD., 40 Lower Sackville Street (to which Address Subscriptions should be sent). London: SIMPKIN, MARSHALL, HAMILTON, KENT, & CO., Ltd. GLEW'S SCINTILLOSCOPE SCREEN PITCH BLENDE (PATENT). Shows a magnificent display of scintillations, showers of sparks, direct from the mineral Pitch blende, Radium, Polonium, Uranium, Thorium, or asy radio-active substance, even a Welsbach mantle con tains sufficient Thorium to excite the very sensitive screen of the Scintilloscope, which is far more sensi tive than the Spinthariscope. The Scintilloscope rivals the most delicate Electroscope as a detector of Alpha rays. The eye sees an inexhaustible shower of stars of white light, giving a very realistic idea of the ceaseless activity of these marvellous substances which are producing the terrific bombardment causing this beautiful display. See NATURE, September 29, page 535Glew's Scintilloscope Superior Lens, with Extra-sensitive Pitchblende and Polonium Screens, giving brilliant effects, Complete, 7s. 6d., Post free, U.K. Foreign Postage extra, weight 2 ounces. Pieces of Pitchblende mineral, ground flat and polished, with Sensitive Radio active supplies of every description, on Sale or Hire. Radium F. HARRISON GLEW, Radiographer (Silver Medallist, Paris, 1900), THE TRAM-CHRONOGRAPH. BY F. JERVIS-SMITH, M.A., F.R.S. 2/- POST FREE. E. MOGRIDGE, 3 ST. GILES, OXFORD. GAMBRELL BROS. ELECTRICAL TESTING INSTRUMENTS. DURHAM HOUSE, NORTH SIDE, CLAPHAM COMMON, LONDON, S.W. MACMILLAN & CO.'S VOLUME VII. NOW READY. LIST. THE CAMBRIDGE NATURAL HISTORY. EDITED BY S. F. HARMER, Sc. D., F. R.S., AND A. E. SHIPLEY, M.A., F.R.S. TO BE COMPLETED IN TEN VOLUMES. FULLY ILLUSTRATED. 8vo. PRICE 175. NET EACH. FISHES (exclusive of the Systematic Account of Teleostei). By T. W. BRIDGE, Sc. D., F.R.S. FISHES (Systematic SIR WILLIAM HENRY FLOWER, K.C.B., F.R.S., LL.D., D.C.L., late Director of the Natural History Museum and President of the Royal Zoological Society. A Personal Memoir. By CHARLES J. CORNISH, M.A., F.Z.S. With Photogravure Portraits. 8vo. 8s. 6d. net. TIMES. "The whole book is pleasantly written in a straightforward style. . . . Furnishes an acceptable memorial of a noble Englishman." NATURE.-"The author is to be decidedly congratulated on the attractive manner in which he has laid before the public the main features of a very interesting and highly successful scientific career." NEW VOLUME BY HENRY SIDGWICK. MISCELLANEOUS ESSAYS AND ADDRESSES. 8vo. IOS. net. AN ELEMENTARY By H. S. HALL, M.A., and F. H. 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WATKINS & DONCASTER, NATURALISTS, AND MANUFACTURERS OF CABINETS AND APPARATUS FOR ENTOMOLOGY, BIRDS EGGS AND SKINS, AND ALL SPECIAL SHOW-ROOM FOR CABINETS. Our Catalogue (96 pp.) Post free on application N.B. For Excellence and Superiority of Cabinets and Apparatus, references are permitted to distinguished patrons, Museums, Colleges, &c. A LARGE STOCK OF INSECTS, BIRDS' EGGS AND SKINS. Birds, Mammals, &c., Preserved and Mounted by First-class Workmen true to Nature. All Books and Publications on Natural History supplied. 36 STRAND, LONDON, W.C. (Five Doors from Charing Cross.) ROCKS, MINERALS, FOSSILS. For Collectors, Students, Technical Schools, Colleges, &c. COLLECTIONS IN POLISHED DEAL BOXES. 25 Specimens, 5/6; 50 do., 10/6; 100 do., 21/-; 200 do., 42/20 Coal Measure Rocks and Fossils, 12/6; do., larger, 15/-. Adapted for the Board of Education Examinations in Geology, Physiography, and Mineralogy. A large stock of Minerals, Rocks, Fossils and Microscopic Objects for NEW CATALOGUE POST FREE. THOMAS D. RUSSELL, 78 Newgate St., London, E.C. ALBERT EDWARD JAMRACH (Late CHARLES JAMRACH), NATURALIST, 180 ST. GEORGE STREET EAST. Implements of Savage Warfare, Idols, Sacred Masks, Peruvian Pottery, Netsukis China, Lacquers, Gongs, Shells, and other Curios. LIVING SPECIMENS FOR THE MICROSCOPE. Volvox, Spirogyra, Desmids, Diatoms, Amoeba, Arcella, Actinosphærium, Vorticella, Stentor, Hydra, Floscularia, Stephanoceros, Melicerta, and many other specimens of Pond Life. Price is. per Tube, Post Free. Helix pomatia, Astacus, Amphioxus, Rana, Anodon, &c., for Dissection purposes. THOMAS BOLTON, 25 BALSALL HEATH ROAD, BIRMINGHAM. MARINE BIOLOGICAL ASSOCIATION OF THE United KINGDOM. THE LABORATORY, PLYMOUTH. The following animals can always be supplied, either living or preserved by the best methods : Sycon; Clava, Obelia, Sertularia; Actinia, Tealia, Caryophyliia, A cyonium; Hormiphora (preserved); Leptoplana; Lineus, Amphiporu, Nereis, Aphrodite, Arenicola, Lanice, Terebella; Lepas, Balanus, Gammarus, Ligia Mysis, Nebalia, Ca c aus; Patella, Buccinum, Eledone, Pectens Bugula, Crisia, Pedicellina, Holothuria, Asterias, Echinus. Ascidia, Salpa (preserved), Scyllium, Raia, &c., &c. For prices and more detailed lists apply to Biological Laboratory, Plymouth. THE DIRECTOR. NOTICE.-Advertisements and business letters for NATURE should be addressed to the Publishers; Editorial Communications to the Editor. The telegraphic address of NATURE is "PHUSIS," LONDON. THE STEREOSCOPIC COMPANY'S C. E. MÜLLER, ORME & CO., ARTIST'S LTD. CONTRACTORS TO HIS MAJESTY'S GOVERNMENT, 148 HIGH HOLBORN, LONDON, W.C. MANUFACTURERS OF APPARATUS FOR TEACHING CHEMISTRY, PHYSICS, MECHANICS, HYDROSTATICS, &c. DEALERS IN PURE AND COMMERCIAL CHEMICALS. STUDENTS' SETS OF APPARATUS. LISTS:- Chemical Apparatus-Chemicals-Balances-Assay REFLEX Thermometers-Electrical Apparatus-Focus Tubes, X-Ray, THE LONDON STEREOSCOPIC COMPANY, and Wireless Telegraphy Apparatus-or SPECIAL WHOLESALE (for Quantities)-free on application. 106 & 108 REGENT ST., W., or 54 CHEAPSIDE, E.C. ESTABLISHED OVER 60 YEARS. Printed by RICHARD CLAY AND SONS, LIMITED, at 7 & 8 Bread Street Hill, Queen Victoria Street, in the City o London, and pubished by MACMILLAN AND CO., LIMITED, at St. Martin's Street, London, W.C., and THE MACMILLAN COMPANY, 66 Fifth Avenue, New York.-THURSDAY, Dec. 15, 1904. Containing an original description of the principles and function of the photographic lens. Together with the latest workshop methods. Then there follows a series of chapters on practical photography and the effect of lenses on results. The chief types are discussed and compared by means of original diagrams. Also an appendix on the Gauss Theory and on a new system of lens testing. The book is entitled "PHOTOGRAPHIC LENSES: A SIMPLE TREATISE." 350 Pages, 45 Engravings, 150 Diagrams, Cloth Bound. CHEMICAL AND PHYSICAL BENCH, illustrated above, as suppliep NEGRETTI & ZAMBRA'S SELF-RECORDING METEOROLOGICAL INSTRUMENTS. THE NEW PATTERN COMBINED BARO-THERMOGRAPH. VERY SUITABLE FOR A CHRISTMAS PRESENT. |