Special display for Teachers and Students on Saturdays. Open till 7 p.m. RICHARDS' SHOW ROOMS, 3 Beauchamp Place, Brompton Road, South Kensington, London, S.W. MICROSCOPICAL PETROGRAPHY. Gentlemen interested in the above study are invited to send to JAMES R. GREGORY & CO., 1 Kelso Place, Kensington Court, London, W., for a Prospectus of THE TWENTIETH CENTURY ATLAS OF LIVING SPECIMENS FOR 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 Sycon; Clava, Obelia, Sertularia; Actinia, Tealia, Caryophyllia, Alcyonium; Hormiphora (preserved); Leptoplana; Lineus, Amphiporus, Nereis, Aphrodite, Arenicola, Lanice, Terebella; Lepas, Balanus, Gammarus, Ligia Mysis, Nebalia, Carcinus; 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. NOTICE.-Advertisements and THE DIRECTOR. THE NEW COLLECTION OF 336 SPECIMENS AND SLIDES OF ROCKS, according to H. ROSENBUSCH: "Elemente der Gesteinslehre, 2d ed. 1901." Accompanied by a text-book: "Practical Petrography," giving a short description of the polarizing microscope and its application, and also of the macroscopical and microscopical features of every specimen of this collec tion, by Professor Dr. K. Busz of the University of Münster. This collection is intended for the practical use of students, and contains typical representatives of all important types of rocks; it is composed of 277 massive rocks (94 deep-seated rocks, 50 dike rocks, 133 volcanic rocks), 28 sedimentary, and 31 crystalline schists. Out of it two smaller collections of 250 and 165 specimens have been selected. The prices are as follows:Collection I. 336 Specimens of Rocks 380 Marks. COLLECTIONS OF MINERALS, FOSSILS, METEORITES, PURCHASED FOR CASH OR EXCHANGED. The fifth edition of Catalogue No. 4, Petrography, has just been published (210 pages), and will be sent free of charge on application. Dr. F. KRANTZ, RHENISH MINERAL OFFICE, BONN-ON-RHINE, GERMANY. ESTABLISHED 1833. 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, references are permitted to distinguished patrons, Museums, Colleges, &c. A LARGE STOCK OF INSECTS, BIRDS' EGGS AND SKINS. SPECIALITY.-Objects for Nature Study, Drawing Classes, &c. 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.) New Catalogue (102 pp.) just issued, post free. 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 THOMAS D. RUSSELL, 78 Newgate St., London, E. C. business letters for NATURE should be addressed to the Publishers; Editorial Communications to the Editor. The telegraphic address of NATURE is " PHUSIS," LONDON. SUBSCRIPTIONS TO "NATURE." £ s. d. TO ALL PLACES ABROAD:- £ s. d. 1 8 0 CHARGES FOR ADVERTISEMENTS. £ s. d. £ s. d. Yearly Half-yearly 0 14 6 I 10 6 o 15 6 One Sixteenth Page, or Eighth Col. 10 6 | Quarter Page, or Half о O 9 a Column I 15 O o 18 Half a Page, or a Columa 3 5 6 Whole Page . 66 • The first line being in heavy type is charged for as Two Lines. Cheques and Money Orders payable to MACMILLAN & CO., Limited. OFFICE: ST. MARTIN'S STREET, LONDON, W.C. C. E. MÜLLER, ORME & CO., CONTRACTORS TO HIS MAJESTY'S GOVERNMENT, 148 HIGH HOLBORN, LONDON, W.C. MANUFACTURERS OF APPARATUS FOR TEACHING LTD. CHEMISTRY, PHYSICS, MECHANICS, HYDROSTATICS, &c. DEALERS IN PURE AND COMMERCIAL CHEMICALS. STUDENTS' SETS OF APPARATUS. LISTS:-Chemical Apparatus-Chemicals-Balances-Assay-Thermometers-Electrical Apparatus-Focus Tubes, X-Ray, and Wireless Telegraphy Apparatus-or SPECIAL WHOLESALE (for Quantities)-free on application. 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 24, 1905. PHOTOGRAPHIC LENSES. A SIMPLE TREATISE. By CONRAD BECK and HERBERT ANDREWS. 1/-, Post Free 1/3. This somewhat difficult subject is made clear without the use of mathematics. R. & J. BECK, Ltd., 68 CORNHILL, LONDON. W. G. PYE & CO., SCIENTIFIC INSTRUMENT MAKERS, GRANTA WORKS, CAMBRIDGE. Free on application to NEGRETTI & ZAMBRA'S LONG RANGE BAROMETERS THE DIAGONAL BAROMETER.-In this instrument the tube is much longer than usual, and at the point on the vertical column where in ordinary Mercurial Barometers the 28 inches would be marked, the tube is bent at an angle and the remaining 3 inches of the scale-viz.: 29, 30, and 31are extended over a tube 36 inches long. The mercury now moving diagonally instead of vertically, travels over 12 inches of the tube to every inch on the vertical scale. The slightest variation, even or" to which the scale is divided, is at once noticeable and can be easily read without the aid of a vernier or magnifier. Further Particulars and Prices of this and other long R. & J. BECK, Ltd., 68 CORNHILL, LONDON. BRANCHES 45 CORNHILL, AND 122 REGENT STREET, PRACTICAL NOTES ON TELEPHOTOGRAPHY. ATTENDANCE. For the Course. Physics... For one year. In Anatomy, Practical Anatomy and Physiology for three years, with single attendances at the Courses in Practical Physiology, Organic Chemistry (Preliminary Scientific, Part II.) and Pharmacology and Materia Medica. £3 35. per subject. } For three months. }£4 45. per subject. } For the Course. (B) FOR COURSES FOR EXAMINATIONS BY THE Course. CONJOINT BOARD. FEE. 1.-First Examination- } £21 os. (Parts I., II., III.) Repetition } (Chemistry, Physics, £3 35. per subject. } Biology). } ATTENDANCE. For the Course. For the Course. For three years, with single attendances at the Practical Physiology Courses. For three months. For each three months' work beyond the three years. Mathematics Botany F. E. FRITSCH, Ph.D., B.Sc. H. W. UNTHANK, B.A., B.Sc. Geology & Mineralogy GEO. F. HARRIS, F.G.S. Assaying, Metallurgy & Mining. GEO. PATCHIN, A.R.S.M. RESEARCH in Chemistry and Physics in well-equipped laboratories. French, German, Spanish, Russian, Dutch, & Italian Classes. EVENING CLASSES also in Biology, Physiology, Practical Geometry, Building and Machine Construction, Steam, Theoretical and Applied Mechanics, Land and Quantity Surveying, and Estimating. Calendar 6d. (post free 8d.), on application to the SECRETARY. CITY OF LONDON COLLEGE. ACTING IN CONJUNCTION WITH THE LONDON CHAMBER OF COMMERCE. WHITE ST., and ROPEMAKER St., Moorfields, e.C. (Near Moorgate and Liverpool Street Stations.) PRINCIPAL: SIDNEY HUMPHRIES, B.A., LL.B. (Cantab.) Michaelmas Term begins Monday, October 2nd. EVENING CLASSES in ALL BRANCHES of SCIENCE Well-equipped LABORATORIES for Practical Work in CHEMISTRY, BIOLOGY, BOTANY, GEOLOGY, and all branches of PHYSICS. Special Courses for London University Matric., Inter., and Final B A. B.Sc., Conjoint Board, Pharmaceutical and other examinations. Classes are also held in all Commercial Subjects, in Languages, Literature and Art. All Classes are open to both sexes. SATURDAY COURSES for Matric.. Inter., and Final B.A., B.Sc. DAY COMMERCIAL and HIGHER COMMERCIAL SCHOOLS Prospectuses, and all other information, gratis on application. DAVID SAVAGE, Secretary ST. THOMAS'S HOSPITAL, (UNIVERSITY OF LONDON.) The WINTER SESSION will COMMENCE on OCTOBER 2. The Hospital occupies one of the finest sites in London, and contains 603 Beds. Entrance and other Scholarships and Prizes (26 in number), of the value of more than £500, are offered for competition each year. Upwards of 60 Resident and other Appointments are open to Students after qualification. A Students' Club forms part of the Medical School Buildings, and the Athletic Ground, nine acres in extent, situated at Chiswick, can be reached in forty minutes from the Hospital. A Prospectus, containing full particulars, may be obtained from the Secretary, Mr. G. Q. Roberts. J. H. FISHER, B.S.Lond., Dean. PRELIMINARY SCIENTIFIC EXAMINATION, UNIV. LOND. A Systematic Course of Instruction, including Practical Work, is given at St. Thomas's Hospital Medical School, Albert Embankment. Full particulars may be obtained from the DEAN. Attendance on this Course counts as part of the five years' curriculum. THE VICTORIA UNIVERSITY OF MANCHESTER. SESSION 1905-6. The Session will commence on Wednesday, October 4 next. The following prospectuses may be obtained on application to the REGISTRAR: FACULTIES OF ARTS AND SCIENCE. FACULTY OF LAW. FACULTY OF MUSIC. FACULTY OF COMMERCE. FACULTY OF THEOLOGY. FACULTY OF MEDICINE. DEPARTMENT OF EDUCATION. DEPARTMENT OF ENGINEERING. DENTAL DEPARTMENT. PHARMACEUTICAL DEPARTMENT. PUBLIC HEALTH DEPARTMENT. For other Scholastic Advertisements, see pages claix, clxx, Professor-G. H. LEONARD, M.A. (Camb.). English Literature and Professor-R. P. CowL, M.A. (Trinity Coll., Language Classics Dublin). Professor-FRANCIS BROOKS, MA (Oxon.). Le turers in Chemistry, Mathematics, Physics, Engineering, Botany, Physiology, Logic and Economics, History and Literature, Greek, Latin, Hebrew, French, German, Italian, Oriental Languages, and Music. Lady Tutor-Miss MARGARET J. TUKE, M.A. Full courses in preparation for the Engineering, Medical, Scientific and JAMES RAFTER, Registrar and Secretary. WESTMINSTER HOSPITAL MEDICAL SCHOOL, CAXTON STREET, S. W. A SCHOOL OF THE UNIVERSITY OF LONDON. The WINTER SESSION will commence on MONDAY, OCTOBER 2, 1975. Scholarships of the aggregate value of £320 are offered to students entering in October. Examination on September 26 and 27. Fees 110 Gns. if paid in one sum on entrance. For University Students and those who have completed their anatomical and physiological studies 70 Gns. Special opportunities for Clinical work and for holding the various hospital appointments. Dental students are specially provided for. Prospectus and further particulars may be obtained from the DEAN. KING'S COLLEGE, LONDON. Full Courses for Matriculated Students in Arts, Laws. Science, Engineering, Medicine, and Theology at Composition Fees; or Students may attend the separate Classes. Preparation for all Examinations of the London University. For Prospectuses and all information apply to the SECRETARY, King's College, Strand, W.C. WOMEN'S DEPARTMENT, KENSINGTON. For other Scholastic Advertisements, see pages clxviii, clxx, and clxxi. THE GLASGOW AND WEST OF SCOTLAND TECHNICAL COLLEGE, GLASGOW. SESSION begins TUESDAY, SEPTEMBER 26, 1905, in the new buildings recently erected for the College. The Diploma of the College is granted in the following Departments:CIVIL ENGINEERING, MECHANICAL ENGINEERING, ELEC. TRICAL ENGINEERING, MINING, NAVAL ARCHITECTURE, CHEMISTRY, METALLURGY, MATHEMATICS and PHYSICS. In conjunction with the Glasgow School of Art a Course for a Joint Diploma in Architecture has been arranged. The Courses of Study for the Diploma usually extend over three Sessions. The Average Fee per Session is 12 125. Special Courses for individual Students are arranged as required. Holders of the Diploma are eligible for the Degree of B.Sc. in ENGINEERING of the UNIVERSITY OF GLASGOW after attendance for at least one Session upon pre. scribed University Classes. New and well-equipped Laboratories in the Departments of Physics, Chemistry, Technical Chemistry, Metallurgy, Mechanics, Mechanical and Electrical Engineering have been provided. The Preliminary Examination for Candidates for the Diploma begins on September 18. Names of intending candidates must be lodged not later than September 15, on forms which will be sent on application. CALENDAR (price, by post, 15. 4d.) and PROSPECTUS (gratis) will be sent on application to the SECRETARY. WIGAN MINING & TECHNICAL COLLEGE. Principal-THOMAS T. RANKIN, C.E., B.Sc., M. Inst. M.M., M.I.M.E. SANDWICH SYSTEM OF MINING TRAINING. Opening date, MONDAY, OCTOBER 2, at 9 a.m. Complete Diploma Course extends over a period of three or four years. Two Prizes of £10 10s. each awarded annually. Candidates for Colliery Managers' Certificates of Competency holding the above Diploma will be exempt from two out of the five years' practical experience required oy the Coal Mines Regulation Act. The Home Secretary has approved for the purposes of the Coal Mines Regulation Act (1887) Amendment Act, 1903, the Diplomas of this College. Prospectus post free on application to the PRINCIPAL, or T. RATCLIFFE ELLIS, Hon. Sec. |