Just Published. 3/ ELEMENTARY net. MICROSCOPY. x 179 By F. SHILLINGTON SCALES, F.M.S. Pp. xii + with 78 Illustrations. "This is an admirable work containing exactly the information required by everyone who has occasion to use the microscope as an instrument of research. The volume contains much that ought to be, but is not, known to many who regard themselves as expert microscopists, and a more practical handbook on the microscope does not exist."-Pharmaceutical Journal. London: BAILLIÈRE, TINDALL AND COX, 8 Henrietta Street, Covent Garden. The Official Organ of the British Electrotherapeutic Society. MEDICAL ELECTROLOGY AN INTERNATIONAL MONTHLY REVIEW COVERING THOMAS PRINCE, SCIENTIFIC BOOKSELLER. All books advertised and reviewed in NATURE are supplied at lowest cash prices. Orders by post promptly dispatched. 85 PRAED STREET, LONDON, W. DAVID NUTT, 57-59 Long Acre, London, W.C. Importer of Foreign Literature and Publisher. All FOREIGN WORKS reviewed in NATURE are on sale or can be procured at shortest notice from DAVID NUTT, at Continental Prices. SUBSCRIPTIONS can be effected through DAVID NUTT to all FOREIGN PERIODICALS. RARE and OUT OF PRINT FOREIGN WORKS sought for without charge, and supplied at the most moderate prices. SECONDHAND FOREIGN CATALOGUES supplied regularly on demand, and orders executed therefrom. TO SCIENTIFIC MEN ABROAD English Books (New and Second-hand) and Periodicals promptly supplied at lowest rates. German and French Banknotes and Stamps received in payment. References in all parts of the world. W. MULLER, Export Bookseller, London, W. 59 CASTLE STREET EAST, OXFORD STREET. SCIENTIFIC AND EDUCATIONAL BOOKS NEW & SECOND HAND. LARGEST STOCK in LONDON of SECOND- Mathematical, Theological, and Foreign Books. KEYS AND TRANSLATIONS. 104 CHARING CROSS ROAD, For MATRICULATION, B.A., SCHOLARSHIPS, and FESSIONAL PRELIMINARIES. Tuition in Latin, Greek, French, German, Italian, Mathematics, Mechanics, Physics, Chemistry. Psychology, Logic, Political Economy, Book-keeping. The Staff includes Graduates of Oxford, Cambridge, London, and Royal Universites.-Address Mr. J. CHARLESTON, B.A, Burlington Correspond- FOR SALE. X-Rays Outfit. 10" Apps Coil, ence College, Clapham Common, London, S.W. EGYPTIAN GOVERNMENT SCHOOLS. 6 "Q21" accumulators, stand, tubes, sundries, in good working order. Also 6" Apps Coil and 6" Harvey and Peak Coil. Can be seen by appointment, London Stereoscopic Company, 54 Cheapside. - For Sale. "Nature," 1903, 1904, 1905 (to date), and nine numbers 1902. Offers to "R.," c/o NATURE. HIGHLY EDUCATED WOMEN ACCUSTOMED TO SCIEN- In view of the extension of Secondary Education in Egypt, applications are invited for new ASSISTANT-MASTERSHIPS in Secondary Schools under Ministry of Public Instruction. Masters to begin work in September, in Cairo or Alexandria, and to teach in English exclusively. Over 400 boys TYPE-WRITING UNDERTAKEN BY in each school, mainly Mohammedans. In the case of one of the Masters now required, the subject mainly essential is Science (Experimental Physics and Chemistry); six of the new Masters will be principally engaged in teaching Mathematics (Arithmetic, Geometry, and Algebra); the others will be concerned more particularly with the teaching of English. Candidates must be not less than 23 nor over 30 years of age, have a robust constitution, and have taken a University Degree in Honours. They must have experience as Teachers: preference will be given to applicants who hold a Diploma in Teaching. Salary, £295 per annum (Eg.24 per mensem), rising to £393 per annum (Eg. 32 per mensem). Allowance for passage out to Egypt. Teaching hours, on an average, four daily, Fridays only excepted. Summer vacation not less than two months. Applications, with full statement of qualifications, and accompanied by copies only of testimonials, must be sent in before May 15, 1905, marked outside Assistant Masterships," and addressed to the SECRETARYGENERAL, Ministry of Public Instruction, Cairo, Egypt, to whom candidates may apply for further information. SCHOOL OF AGRICULTURE, JUNIOR LECTURER IN AGRICULTURE. Candidates must be not less than 23 nor over 33 years of age, have a robust constitution, and possess a University Degree or College Diploma in Agriculture. Preference will be given to applicants having experience of Agricultural Practice and Teaching. In addition to Agriculture, the Lecturer appointed will be required to teach elementary Agricultural Botany and Entomology. Salary, £295 per annum (Eg.24 per mensem), rising to £393 per annum (Eg.32 per mensem). Allowance for passage out to Egypt. Applications, with full statement of qualifications, and accompanied by copies only of testimonials, must be sent in before May 4, 1905, to W. C. MACKENZIE, Esq., D.Sc., Principal, School of Agriculture, Ghizeh, Egypt, to whom candidates may apply for further information. UNIVERSITY COLLEGE OF WALES, The COUNCIL invites applications for the post of REGISTRAR and near TO SCIENCE AND MATHEMATICAL APPLICATIONS are invited for the First Sales by Auction. PALL MALL. On View. The Collection of Minerals of the late MESSRS. FOSTER respectfully announce for SALE by AUCTION, at the Gallery, 54 Pall Mall, to-morrow, Friday, April 14, at I o'clock precisely, PART of the extensive and valuable COLLECTION of MINERALS, including fine specimens of Cornish Uranites, Cuprites, Liroconites, &c., Gold Specimens and Chalcedonies, also several well-made Cabinets. May be viewed and Catalogues had, 54 Pall Mall. NATURAL HISTORY SPECIMENS. MR. J. C. STEVENS will Offer at his Catalogues and all particulars on application. ALFRED E. DEAN, THE LARGEST MAKER IN ENGLAND of Apparatus in all Departments of ELECTRO-THERAPEUTICS including Radiography, High Frequency, Hydro-Electric and LISTS ON APPLICATION. 82 HATTON GARDEN, LONDON. MICROSCOPIC SLIDES, MARINE OBJECTS, Hydrozoa extended without pressure, sponge sections, &c. Apply for Lists. Dispersal of Mr. HORNELL'S collection. Flower and Leaf Buds, Stems, Roots, &c., new, from 3. each. Lists. Exhibition Groups of Diatoms, &c, in symmetrical patterns. EDINBURGH H., by Watson, for sale, and others; several Objectives, Condensers, &c. PRISMATIC BINOCULARS, LANIERN SLIDES, Church Architecture, Swiss, Egypt and Holy Land views, all first class. Fine mounted collection of Grasses, Mosses, Ferns, Marine Algæ. Detailed List sent on application, as stock is always changing. Mr. HERBERT CLARKE, 104 LEADENHALL STREET, E.C. With 30 Original Illustrations. Price 2s. 6d. A Guide to the Prevention and Control of Dental Diseases. BY THE SAME AUTHOR. The DISEASES of CHILDREN'S TEETH Well Illustrated. Price 75. 6d. SEGG & CO., 289 and 291 Regent Street, London W. WARNING. Observe that the Regulator of Burner, Body of Furnace, and Hood are all distinctly stamped in the metal "BREWSTER, SMITH & Co., LONDON." Beware of imitations that do not contain the essential feature of this burner's success. MARBLE REDUCED TO QUICKLIME IN 10 MINUTES with our NEW BLAST BUNSEN BURNER AND MIDGET FURNACE. We make these in two sizes at present," and ", and the prices are-Burners only, 1/6 and 2/6; complete with Furnace, 4/6 and 6/-. The consumption of gas is the same as with an ordinary Bunsen, but the heat derived is three times as great, and a number of interesting experiments can be performed with them, which have only been possible before with very expensive furnaces. We are the SOLE MAKERS. NATURE says:-"The combination of furnace and burner is very convenient. These little furnaces are not only useful for reducing calcium carbonate to lime, but also work very well in fusion experiments." BREWSTER, SMITH & Co., 6 CROSS ST., FINSBURY PAVEMENT, LONDON. Makers and Importers of every description of Scientific Apparatus and Chemicals. LABORATORIES FITTED & FURNISHED THROUGHOUT. SECOND-HAND TELESCOPES. 6 in. Dallmeyer Equatorial, Clock, complete, £100. 4 in. Alvan Clark, Equatorial by Cooke, £50. Several 3 in. Student Telescopes, by leading makers, £4 10s., £6 10s., £8 10s., £10. SECOND-HAND SPECTROSCOPES, Single, 2, and 3 Prism, by Browning, £4 10s., £8 10s., £10. SECOND-HAND MICROSCOPES. Watson's Edinburgh H., 3 powers and fittings, complete, as new, £16 10s. Swift Army Bacteria, complete, £15. Leitz 2b, with rack, substage, and fittings, £6 10s. MANY OTHERS, ALL KINDS. LISTS ON APPLICATION. A. CLARKSON & CO., 28 BARTLETT'S BUILDINGS, HOLBORN CIRCUS, LONDON. and Chemical completely fitted up. Illustrated Price £10 10 0 Including dense flint glass prism, with micrometer movement, reading to 1 minute. Universally acknowledged to be the most MAKER OF PHYSICAL, ASTRONOMICAL, AND OTHER INSTRUMENTS.. COX'S NEW PORTABLE W. WILSON, HIGH FREQUENCY APPARATUS Maker of GIVING GENUINE H.F. CURRENTS FROM A NEW FORM OF OUDIN RESONATOR. Descriptive Leaflet and Price post free. ILLUSTRATED CATALOGUE in X-RAYS, &c. (including HARRY W. COX, Ltd., FACTORY AND OFFICES 1a ROSEBERY AVENUE, & 15-21 LAYSTALL ST., LONDON, E.C. A RECENT COMMENT UPON The SYTAM SYSTEM "Your System will assuredly revolutionize the present method-or want of methodin fitting up Laboratories, Libraries and Offices." The Sytam Bottle Element. Patent No. 7463. This Bottle Element is substantially a Drawer, and is operated as such. It can be placed in a cupboard or underneath a bench or table, or several can be supplied in a suitable outer casing to form a complete cabinet. One hundred 4 oz. bottles occupy less than 1 sq. ft. of wall space, each bottle is instantly located, removed or replaced, and any size from oz. to a Winchester can be accommodated in one and the same element. PRICES Single Element, without shelves, £1 0 0 Ditto, with complete fittings, £1 15 0. Standard Cabinet of 6 Elements variously fitted, Bottles extra, £11.11 0. 17/6, post paid. 16 Oz. Facsimile of a bar Further Important Reduction in Price of CALCIUM METAL 99.3 to 99.6 per cent. Electrolysis from The mahogany table has two coils of insulated wire arranged one behind the other, the ends of which are brought to terminals in front, marked with negative and positive signs respectively. With this instrument the current may be passed and the field mapped out when it passes, first, through one coil only; second, through both coils in the same direction; third, through both coils in the opposite direction; fourth, through one coil when a bar magnet is placed opposite to the face of the coil, its length being perpendicular to the plane of the coil; fifth, repeated when the current is reversed in direction. Price, with brass wire sieve complete, 21/ ARMBRECHT, NELSON & CO. 71 & 73 Duke St., Grosvenor Square, LONDON, W. Telephone-Gerrard 4942. Just arrived, fresh CARBORUNDUM or SILICIUM CARBIDE (Beautiful show crystals), 2/- per oz., in lumps of 2 oz. upwards. |