Electric Current for 100 16-c.p. lamps can be obtained for ONE PENNYWORTH of fuel per hour by using a CROSSLEY CROSSLEY BROS.. LTD., OPENSHAW, MANCHESTER. WATSON'S MICROSCOPES & OBJECTS. Watson's New "Club" Microscope. An Instrument of full size of most modern design. Especially arranged for the use of Amateurs. Monocular, £15; Binocular, £18. Watson's well-known Van Heurck and Edinburgh Student's Micro- The Watson-Conrady Condenser System is of new computation, and for the Microscopist. Everything For all the above see WATSON'S 158-page Catalogue of Microscopes, sent SPECIALITIES: post free. New Slide of Radium for Microscope. Shows Scintillations Trypanosoma Brucei (Sleeping Sickness) each 6000 26 Exquisite arranged groups composed of Diatoms. Spicules, &c, Write for Catalogue No. 3 of Micro. Objects, together with ne ly (SPINTHARISCOPE for observing the Scintillations of Radium. The very best. Price 21/- ESTABLISHED 1837. BRANCH-16 Forrest Road, Edinburgh. Printed by RICHARD CLAY AND SONS, LIMITED, at 7 & 8 Bread Street Hill, Queen Victoria Street, in the City of London, and pub NATURE A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE "To the solid ground Of Nature trusts the mind which builds for aye."-WORDSWORTH. COUNTY OF LONDON. EDUCATION ACTS, 1870 TO 1903. The London County Council invites applications for the following appointments in the Education Department : FOUR DIVISIONAL INSPECTORS, who will have the general superintendence of large districts and give special attention to the co. ordination of education within their areas. Their chief duties will be to inspect pupil teachers' centres, secondary schools, training colleges, science and commercial centres, polytechnics, and all institutions for higher educa tion aided by the Council. Candidates will be required to possess special qualifications in one of the following subjects :-(1) English language and literature; (2) Modern languages; (3) Mathematics and Science; (4) Technology (including mechanical and electrical engineering). The salary will be in each case £60 a year, rising by annual increments of £25 to a maximum salary of £800 a year. ONE ART INSPECTÓR, whose chief duties will be to inspect the art teaching in elementary and secondary schools, art schools and polytechnics. The salary will be 6400 a year, rising by annual increments of £20 to a maximum salary of £500 a year. ONE INSPECTOR of WOOD and METAL WORK, whose chief duties will be to inspect the teaching in wood and metal work in manual training centres and elementary and secondary schools. He will also be required to inspect certain classes at polytechnics. The salary will be £400 a year, rising by annual increments of £20 to a maximum salary of £500 a year. ONE INSPECTOR of WOMEN'S TECHNICAL CLASSES, whose UNIVERSITY OF BIRMINGHAM. chief duties will be to inspect technical classes for women (including upholstery, flower making, needlework, millinery, dressmaking and dress. cutting) in evening schools, girls' clubs and polytechnics. The salary will be £300 a year, rising by annual increments of £20 to a maximum salary of £400 a year. The persons appointed will be under the control of the Chief Inspector, and will be required to give their whole time to the duties of the office, and will in other respects be subject to the usual conditions attaching to the Council's service, particulars of which are given in the form of application. In connection with the appointments there is no restriction with regard to SIR WM President: DR. R. T. GLAZEBROOK, M.A., F.R.S., Director of the National Physical Laboratory. de WiveleslIE ABNEY, K.C.B., D.C.L., F.R.S. THE RIGHT HON. THE EARL OF CRAWFORD, K.T., LL.D., F.R S. THE RIGHT HON. THE LORD KELVIN, O.M., G.C.V.O., F.R.S. THE OPTICAL CONVENTION will be held at the NORTH- The object of the Convention is to bring into co-operation those interested in Optical Matters, from all sides of the question, theoretical, practical, and commercial. The mornings will be devoted to papers and discussions on Optical subjects. These will be collected in a volume to be issued by the Convention. There will be an EXHIBITION OF OPTICAL & SCIENTIFIC INSTRUMENTS of British manufacture, in the large hall of the Northampton Institute, during the Convention, open daily from 12 to 10 p.m. In connection with this, a catalogue is in preparation, which will be a useful work of reference in regard to instruments manufactured in this country The Subscription for Membership of the Convention will be five shillings. Applications for membership should be a dressed to the Hon. Sec., Mr. F. J. SELBY, M.A., Elm Lodge, Teddington, Middlesex, who will be glad to furtish further particulars if desired. ADMISSION to the Exhibition, daily, ONE SHILLING, after 7 p.m., Sixpence. Tickets admitting to the Exhibition at any time while it is open, 2 6. Faculties. SCIENCE, ARTS, MEDICINE, COMMERCE. ENGINEERING, METALLURGY, MINING, BREWING, Leading to Degrees and Diplomas. ALL COURSES AND DEGREES ARE OPEN TO BOTH MEN AND WOMEN STUDENTS. In the Medical School there is a separate Dissecting Room for Women with a qualified Woman Demonstrator. Graduates of other Universities may, after two years' study or research, take a Master's Degree. Syllabuses with all information will be sent on application to the SECRETARY. THE SIR JOHN CASS TECHNICAL JEWRY STREET, ALDGATE, E.C. A Course of Twelve Lectures and Demonstrations on will be given during the Summer Term by G. SENTER, B.Sc., Ph.D., Lecturer on Chemistry at St. Mary's Hospital Medical SoonThe Lectures and Demonstrations will be held on Wednesday Evenings, 7-9 p.m., commencing Wednesday, March 29. The Course is arranged for students of Chemistry and Physics *** those engaged in Chemical and Electrical industries, who desire to c'tar a knowledge of the modern developments of Physical Chemistry. It will also be adapted to the requirements of candidates for the ** B.Sc. examination of London University. A Course of Laboratory Work in connection with the lectures wil be held on Wednesday afternoons. A detailed Syllabus may be had upon application at the Office of t Institute or by letter to the PRINCIPAL. W. H. DAVISON, M.A., Clerk to the Governing la Short Courses suitable for the Intermediate and Final B. Sc. Exam Ta tions of London University will be conducted by Teachers recognised T the University as follows: GEOLOGY.-A. J. MASLEN, F.L.S. An Excursion (about 5. BOTANY.-T. G. HILL, A.R.C.S., F.L.S. A Summer Crerse = For particulars, apply to the Head of the Natural Science Departme For other Scholastic Advertisements, see page cxciv. BROWNING'S SPECTROSCOPES. The STUDENT'S SPECTROSCOPE has a prism of extremely dense glass, of very superior workmanship; the circle is divided, and reads with a vernier to single minutes; the slit is furnished with a reflecting prism, by means of which two spectra can be shown in the field of view at the same time. The instrument will divide the D line in the Solar Spectrum, or the yellow Sodium lines distinctly. With a slight alteration of the adjustments, the instrument can be used for taking the refractive and dispersive powers of solids or liquids. The Student's Spectroscope is the best instrument for the Laboratory and for all general work in Spectrum Analysis. ... £7 0 0 £8 16 0 £15 0 0 Complete in Cabinet JOHN BROWNING, 78 Strand, London, W.C. LIQUID AIR AND LIQUID HYDROGEN. Dr. HAMPSON'S AIR-LIQUEFIER is now made to a standard pattern, and numbers are in use in University Laboratories and elsewhere in various countries. The whole apparatus is neat and compact and its parts very easily moved; the Liquefier, without stand, being a cylinder 17 inches high and 8 inches in diameter. It begins to liquefy air in from 6 to 10 minutes after the admission of air at from 150 to 200 atmospheres pressure, making over a litre of liquid per hour. It requires no auxiliary refrigerant and produces a perfectly clear liquid which requires no filtering. The operator has only one gauge to watch and one valve to control. HYDROGEN LIQUEFIER to the designs of Dr. MORRIS W. TRAVERS for use in conjunction with Air-Liquefier. For Prices and Particulars apply to the Sole Makers :BRIN'S OXYGEN COMPANY, LIMITED, ELVERTON STREET, WESTMINSTER, S.W. SANGER-SHEPHERD secure photographs with all the beauty STEWART, LIVETT & CO., 62 Theobalds Road, London, W. (FOUR MINUTES WALK FROM HOLBORN TOWN HALL) JAMES SWIFT & SON'S NEW PAN-APLANATIC OBJECTIVES 1/12" OF THE HIGHEST POSSIBLE OPTICAL EXCELLENCE. Apochromatics. N.A., 1.30, oil immersion Pan-Aplanatics. £8 8 0 8 8 0 £2 5 0 "N.A.. o.80 0.88 0.92 1 16 0 2 17 0 NATURE says:-"In the excellence of their 1/12-in. homogeneous LISTS POST FREE ON APPLICATION. 81 Tottenham Court Road, London. Complete Outfits to attach to Plate Cameras, including Repeating-Back as above, and every requisite, from £8 14 0 NEW ONE-LENS ONE-EXPOSURE CAMERA. Send for New Booklets, post free to readers of "Nature," or call and see results obtained by amateurs. SANCER-SHEPHERD & CO.. 5, 6 & 7, Gray's Inn Passage, Red Lion St., Holborn, London, W.C. MR. ALFRED C. CHAPMAN, F.I.C., EVENING CLASS IN ELEMENTARY This will commence on Monday, April 3rd next, and will consist of about sixteen meetings of two hours each. The Course, whilst dealing more particularly with those organisms which are of importance in the Fermentation Industries, will be found useful to Students who are preparing for the Final. Examination of the Institute of Chemistry in Biological Chemistry or in Branch "É." For Syllabus and all further particulars apply toCHEMICAL LABORATORIES, 8 DUKE STREET, ALDGATE, E.C. UNIVERSITY COLLEGE, LONDON. (UNIVERSITY OF LONDON.) FACULTY OF MEDICINE. The SUMMER SESSION begins on WEDNESDAY, APRIL 26. The work is arranged so that a Student may advantageously begin his Medical Curriculum then. The Bucknill Scholarship and four Entrance Exhibitions will be awarded n October. Full information may be obtained from either of the undersigned. SIDNEY MARTIN, M.D., F.R.S., Dean of the Faculty. WALTER W. SETON, M.A., Acting Secretary. COACHING (THEORY AND PRACTICE) In BIOLOGY, BOTANY, CHEMISTRY and PHYSIOLOGY for MEDICAL EXAMS. Especial Course of Instruction in THERAPEUTICS, PHARMACOLOGY and MICROSCOPY for INSTITUTE OF CHEMISTRY EXAM. Mr. FREDERICK DAVIS, The Laboratories, (Registered in Column B (Advanced Education), Teachers Registration Council, Board of Education, S.W.), 49 and 51 IMPERIAL BUILDINGS, LUDGATE CIRCUS, E.C. SCHOOL OF AGRICULTURE, GHIZEH, EGYPT. JUNIOR LECTURER IN AGRICULTURE. Applications are invited for the post of JUNIOR LECTURER in AGRICULTURE at the School of Agriculture, Ghizeh, under the Ministry of Public Instruction. 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. BOTANY TUTOR. Stipend, £300. WELL KNOWN COLLEGE. 80 Wigmore Street, Cavendish Square, London, W. (late 44 Old Bond Street). FOR SALE. The Instruments in the Observatory of the late Mr. Edward Crossley: a 9-in. and a 4-in. (both photo-visual object glasses) Equatorial Refractor by Cooke; A 32-in. Transit Circle by Cooke; a 6-in. Sextant and a 5-in. Transit Theodolite by Troughton and Simms; Siderial Clock by Cooke; Parallel-wire and Double-image Micrometers by Troughton and Simms; Microscopes by Ross and Zeiss; Apparatus for Lectures on Light, Polarisation, &c., by Harvey and Peak; Measuring Bars and Rods-12-in., 40-in., 3-ft., 10-ft.-by Troughton and Simms; Standard Barometer by Hicks; Two Spectroscopes; Two Controlled ClocksApply to Mr. J. GLEDHILL, Bermerside, Halifax. Skilled mechanic requires situation, Laboratory or Works All round man, has had charge of metal and wood workshops, experi enced in electrical and general scientific apparatus. Can manufacture same on commercial lines.-E. T. Cook, 23 Sandhurst Grove, Leeds For Sale.-Extensive Collections of British Lepidoptera, Coleoptera, Tropical Butterflies, Cabinets, &c. Correctly named type collections at very moderate prices.-Particulars from A. FORD, Hillside, Sunnyhill, Pokesdown, Bournemouth. The UNIVERSITIES of MANCHESTER, TYPE-WRITING LIVERPOOL and LEEDS. The next MATRICULATION EXAMINATION will commence on Wednesday, July 5, 1905, and will be held simultaneously at the three Universities and in Schools approved by the Joint Matriculation Board. The fee is due on or before June 3. Information as to Scholarships awarded on the results of this examination and on other matters may be obtained from the undersigned. R. F. GWYTHER, Secretary to the Joint Matriculation Board, TO SCIENCE, MATHEMATICAL AND OTHER MASTERS.-Required (1) Mathematical Tutor for important Training College. Salary, £140, board and residence. (2) Mathematical Tutor for 1st Grade Public School. £120, board and residence. (3) Science Master for Grammar School, Lond. Univ. man preferred. 120, with residence. (4) Graduate for Mathematics and junior form work. £150, non-res. (5) 2nd Master for Science and Mathematics. 180, non-res. Particulars of the above and other Science posts will be sent on application. Candidates seeking posts for after Easter are invited to apply forthwith. Address, Messrs. Griffiths, Smith, Powell and Smith, Tutorial Agents (Estab. 1833), 34 Bedford Street, Strand, London, W.C. HANDSWORTH GRAMMAR SCHOOL, NEAR BIRMINGHAM. The Governors are prepared to APPOINT a HEAD MASTER, who must be a Graduate of some University of the United Kingdom, to enter upon his duties as soon as possible. Stipend, 150 a year, with Capitation fee of £2 per boy. Present number 140. Accommodation up to 2co; no boarders. Applications, with copies of not more than three recent testimonials, to be sent before April 17, 1905, to H. TRAVERS EDGE, Clerk to the Governors, Waterloo Street, Birmingham. 5 MATHS. and SCIENCE. Attractive Appt. Experienced and successful Army Tutor desires to meet with a Univ. man with above quals., able to take responsibility of Vice-Principal, with view to, later, sharing profits, and a possible partnership. Age 26-32. Salary, £150, res., or £200, non-res. Many other Science Appts. Write or call, NEEDES & SELLICKS, Clock House, Arundel HIGHLY EDUCATED WOMEN ACCUSTOMED TO SCIEN- NEW "DERMA" These rays are being and in America. tively small coil. heals more rapidly Dr. Gu-tav Reus Derma radiation (PATENT APPLIED FOR.) FOR PRODUCING "DERMA"-RAYS, TUBE. Telephone 10547 Central used with good results on the Continent The tubes can be worked with a compara The dermatitis is produced quicker and than that caused by an "X"-ray tube. says: "Our own experience with the proves that a marked but superficial dermatatis is quickly produced by a short exposure to a 'Derma' tube, which is par excellence the apparatus de choix in treating superficial cutaneous affections A. C. COSSOR, 54 Farringdon Road, London, E.C. GOLD MEDAL AWARDED ST. LOUIS EXHIBITION, 1904 SECOND-HAND TELESCOPES, &c. 64 in. ALVAN CLARK, equatorial, much apparatus £150 6 prism SPECTROSCOPE by BROWNING... MICROSCOPES |