May, 1915. 



KNOWLEDGE. 



vu. 



SPRING MICROSCOPY. 



WATSONS 

 "CLUB" MICROSCOPE 



is the Ideal Instrument for Field Work. 



PORTABLE COMPACT 



Is made throughout with the 

 care and consideration of detail 

 which has made the name of 

 "Watson" on a microscope a 

 guarantee of satisfaction. 



A few paints to consider:— 



It packs into a leather sling 

 case 7J X 4J X 3i inches. 

 Accommodation in case for 

 2 eyepieces — 4 objectives — 

 condenser — forceps — dipping 

 tubes — nosepiece. 



A 3" objective can be focussed 

 with ease. 



Every fitting is standard size. 



A Mechanical Stage can be 

 fitted. 



The instrument is adapted for 

 high or low power work. 



Price: Club Microscope as figured eycz g\ fk 



and described, in stiff leather case ... *»0 \J %J 



Send alpostcard for Section I of Catalogue No. 2, Full 

 details of this Stand will be found on page 94. Also 

 details of 32 other instruments at varying prices. 



ALL. ARE BRITISH MADE. 



The "Club" Microscope. 



All bearings slotted and sprung. 



Collecting Apparatus. 



mfammmmimmmmmi* TiT" (hi n n tiiim 



Complete Outfits: 



Silver-mounted best quality cane stick and inner extending 

 rod of hard cane with taper fitting : — 2 bottles — metal clip — 

 metal net ring — cutting hook — spoon for mud — drag hook — 

 line — brass reel. Stick only, 12/6. Complete, £1 1 0. 

 Also Complete Outfits at 15/-, 17/6. 



Full specification of the above, also ColIectingTubes, 



Troughs, Botanical Presses, Geological Apparatus, 



Ac, in CATALOGUE No. 2, Section 2, gratis on 



request. 



WATSONS MICROSCOPIC OBJECTS. 



The most complete collection extant. Over 40,000 specimens, 



all specially selected, and guaranteed typical. Catalogue 



No. 3 gratis. 



No Microscopist should be without Watson's Catalogues. 



Send for your copy to-day and save money on your 



purchases. 



W. WATSON & SONS, LTD., 



Contractors to Ib.dft. ©orernmcnts, 

 313 HIGH HOLBORN, LONDON, W.C. 



Branches : 



16 Forrest Road, Edinburgh; 196 Great Portland Street. London, W. 



DKr6TS : 



2 Easy Row, Birmingham; 78 Swanston Street, Melbourne, Australia; 



212 Notre Dame Street West, Montreal, Canada. 



Optical Works— HIGH BARNET, HERTS. ESTABLISHED 1837. 



THE FOCOSTAT LENS. 



Hiscotf s Patent.) 



THIS Lens fits the handle of a Dissecting Instrument, Mapping 

 Pen, Pencil or Needle, and when once set is always in focus 

 (focostat). 



It fixes on to the handle of the Instrument itself, and never 

 gets out of focus, is always in the exact position, and saves all the 

 worry of a microscope, a watchmaker's eyeglass or a separate 

 lens on a stand. 



For the Botanist, Entomologist, or Zoologist, and for 

 Draughtsmen it is invaluable. As the instrument or pen is moved 

 so the lens follows, and is always in the correct position. 



Those who have hitherto used a watchmaker's eyeglass or 

 lens on a stand will appreciate the enormous advantage of this 

 instrument. 



The lens is very powerful and can be set by means of the 

 universal joints to the exact position to suit the observer's eye, 

 after which it does not require to be altered. 



p*~ See Editorial Notice in Knowledge, May, 1912, page 193. 



— s. d. 



For Botany and Dissecting, complete with needle ... 5 6 

 2 dissecting scalpels, special fine pointed blades (2/- each) 4 O 



Complete set as above 

 For Draughtsmen, complete with mapping pens 



9 6 



R. & J. BECK, Ltd., 68, Cornhill, London, E.C. 



DENT'S CLOCKS 



WATCHES AND CHRONOMETERS 



FOR SCIENTIFIC USE. 



Sidereal op Mean Time Clocks for 

 Observatories, £21 and upwards. 



THREE GRAND 

 and ONE GOLD 



FRANCO-BRITISH 



PRIZES 

 MEDAL 



EXHIBITION. 



The only Grand Prize awarded 

 to a British Firm for Watches 

 Clocks and Chronometers. 



The only Grand Prize awarded 

 for Astronomical Regulators, 

 Chronographs, and Ship' 

 Compasses. 



TRADE MARK 



61, STRAND, and 4, ROYAL EXCHANGE, LONDON. 



Telephone No. 61 City. 



- JOHN KING, ...SrSMt.. - 



UXBRIDGE, SOUTHALL, AND EALING, 



is favourably equipped for the 



PRINTING OF SCIENTIFIC BOOKS, BROCHURES, 4c, 



and will be pleased to submit Estimates. 



Address all Communications to 213, Uxbrldge Road, Eallofj, London, W. 



nnilTintU The Proprietors of SCHWEITZER'S 

 UAU I lUll. " C0C0ATINA,' " FAIRY COCOA, " &c, 

 beg to inform their clients that NONE of their 

 products are manufactured in Germany; that 

 they are a private ENGLISH COMPANY man- 

 aged by a Board of ENGLISH DIRECTORS; and 

 that all shares are held by relatives and con- 

 nections by marriage of the late sole proprietor, 

 Captain Thomas Edward Symons, R.N. 



