A NEW PATTERN FORTIN'S STANDARD BAROMETER Registered Design No. 420,297 As will be seen by the illustration, this 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 extremely accurate and instantaneous reading is made possible. The scales being graduated upon the flat side peces the DIVISIONS AND FIGURES ARE ALWAYS IN VIEW, and the vernier is very much more legible than in the ordinary tubular patterns. The bore of the tube is 0.5 inch. The scales are graduated in inches and millimetres, and, by means of the verniers, are capable of being sub-divided to read to 0.002 inches and 0.1 m/m. The attached Thermometer 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 10s. Od. SMALLER SIZE, "THE STUDENTS," designed for Schools for demonstration work, and small private Observatories; bore 25; reading to 01 inch and 1 millimetre. £3 7s. 6d. Sole Manufacturers and Proprietors of the Regd. Design: NAT. TEL.: 1981 Holborn. Estd. 150 years. N.B.-If any difficulty be found in securing any of our Instruments through your Dealer, kindly communicate with us. REYNOLDS & BRANSON, LTD JOHN J. CRIFFIN & SONS, METALLURGICAL LABORATORIES. Sardinia Street, London, W.C. WAVE-LENGTH SPECTROSCOPE (LARGE MODEL.) Measures wave-lengths direct to an accuracy of 1 Angström unit (one ten-millionth of a metre) from W. L. 3888 to W.L. 7724. SPECIAL ADVANTAGES. The Collimator and Telescope are rigidly fixed at right angles, thus the instrument will stand in a corner, is always ready for use and in adjustment. The wave-lengths can be read off by the observer without moving from his place. The object glasses and prism are large (1 clear aperture), which enables the faintest visible lines to be seen. The eyepiece has a bright pointer for measuring the W.L. of bright lines on a dark field. Means are supplied of very simply setting the Zero, although on account of the great rigidity and careful construction throughout it may be used for many months without any setting being needed. ADAM HILGER, Ltd., 75a Camden Road, London, N.W. AWARDED GOLD MEDAL ST. LOUIS EXHIBITION, 1904. Telegraphic Address:-"Sphericity, London." ILLUSTRATED LIST ("A") OF SPECTROSCOPES AND SPECTROSCOPIC ACCESSORIES GRATIS ON APPLICATION. MACMILLAN & CO.'S SCIENCE CLASS BOOKS. ADAPTED TO THE SOUTH KENSINGTON SYLLABUSES. I.-PRACTICAL PLANE AND SOLID GEOMETRY. Practical Plane and Solid Geometry for Advanced Students. II. MACHINE CONSTRUCTION AND DRAWING. III.-BUILDING CONSTRUCTION. Building Construction for Beginners. By J. W. RILEY, Rochdale Technical School. 2s. 6d. Building Construction for Advanced Students. By J. W. RILEY. [In Preparation. V.-MATHEMATICS. VI. THEORETICAL MECHANICS. Mechanics for Beginners. By W. GALLATLY, B.A. 2s. 6d. VII.-APPLIED MECHANICS. Applied Mechanics for Beginners. By J. DUNCAN, Lessons in Applied Mechanics. By Prof. J. H. COTTERILL, 5s. 6d. VIII.-SOUND, LIGHT, AND HEAT, AND Elementary Lessons in Heat, Light, and Sound. By D. E. Lessons in Heat and Light. By D. E. JONES, B.Sc. 35. 6d. Practical Exercises in Light. By R. S. CLAY, D.Sc. 2. 5d. Elementary Physics. By BALFOUR STEWART, F.R.S. By H. E. X. & XI.-CHEMISTRY-continued. Chemical Problems. By Prof. T. E. THORPE, C.B., With Key. 25. F.R.S. Chemical Arithmetic. By S. LUPTON, M.A. With 1200 Problems. Chemistry for Organised Schools of Science. By S. PARRISHI, 2s. 6d. Practical Inorganic Chemistry. By G. S. TURPIN, M.A., The Junior Course of Practical Chemistry. By F. JONES, Tables for Qualitative Chemical Analysis arranged for the Lessons in Organic Chemistry. By G. S. TURPIN, M.A, Theoretical Organic Chemistry. By J. B. COHEN, Ph.D. 65. XII.-GEOLOGY. By Geology for Beginners. By W. W. WATTS, M.A., F.G.S. 2s. 6d. XIV.-HUMAN PHYSIOLOGY. An Introduction to Nature-Study. By ERNEST STEN- A Manual of Zoology. By T. JEFFERY PARKER, D.Sc., XVII.-BOTANY. Botany for Beginners. By ERNEST EVANS. Second ECONOMY. Elementary Lessons in the Science of Agricultural Practice. XXV. HYGIENE. Hygiene for Beginners. By E. S. REYNOLDS, M.D. 25.64. Hygiene for Students. By E. F. WILLOUGHBY, M.B. XXVI.-ELEMENTARY SCIence of comMON LIFE. 4s. 6d. MARINE ORGANISMS, Hydrozoa, Crustacea, Annelida, &c., polyps extended, without pressure, dark ground or opaque, very beautiful. List. Exhibition Groups of Diatoms, Petrological, &c. Dispersal of Mr. HORNELL'S collection of Slides, Marine and Botanical, from 3d. each. MICROSCOPES, &c. SECOND-HAND, large and ever-changing stock. Van Heurck, new, others including Objectives, Condensers, Polariscopes, &c., by Watson, Ross, Powell and Lealand, Beck, Pillischer Reichert, Leitz, &c. Prismatic Binoculars, Lantern Slides, Mounting Materials. Lists. Mr. HERBERT CLARKE, 104 LEADENHALL STREET, LONDON. Tel.-1316 CENTRAL. 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 selection. Specimens sent on approval. Cabinets, Geologists' Hammers, Chisels, Card Trays, Glass-capped Boxes, Models of Crystals, &c., &c. NEW CATALOGUE POST FREE. THOMAS D. RUSSELL, 78 Newgate St., London, E.C MICROSCOPICAL PETROGRAPHY. Gentlemen interested in the above study are invited to send to THE TWENTIETH CENTURY ATLAS OF Subscription in advance, either Monthly, 7/-; Quarterly, 21/.; or for the whole Series of 12 Monthly Parts & 48 Sections, £4 4s. WATKINS & DONCASTER, Naturalists and Manufacturers of CABINETS AND APPARATUS FOR ENTOMOLOGY, BIRDS' EGGS AND SKINS, AND ALL SPECIAL SHOW-ROOM FOR CABINETS. N. B. For Excellence and Superiority of Cabinets and Apparatus, refer Birds, Mammals, &c., Preserved and Mounted by First-class MARINE BIOLOGICAL ASSOCIATION Sycon; Clava, Obelia, Sertularia; Actinia, Tealia, Caryophyllia, Alcy- LANTERN THE DIRECTOR. Palms, Insectivorous Plants, &c.-For lists apply L. FARMAR, 6 Mortlake Terrace, Kew. PHOTOMICROGRAPHY for Publishers, Lecturers, Manufacturers, and general scientific research. Good work, moderate charges.-SAXBY, 91 Penny Lane, Sefton Park, Liverpool. 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LENSES & ATTACHMENTS THE CELEBRATED DALLMEYER LENSES. (These Attachments can be fitted to any good Lens.) Printed by RICHARD CLAY AND SONS, LIMITED, at 7 & 8 Bread Street Hill, Queen Victoria Street, in the City of London, and published by MACMILLAN AND CO., LIMITED, at St. Martin's Street, London, W.C., and THE MACMILLAN COMPANY, 66 Fifth Avenue, New York.-THURSDAY, August 31, 1903. |