NA TURE 



May 



1 1. 1905 



GAIFFE-D ARSONVAL MACHINE 



Replaces Coils, Interrupters, and Wimshurst 

 Machines. 



Producing, perfectly regulating, and exactly measuring 



X-RAYS, HIGH-FREQUENCY CURRENTS, AND 

 STATIC EFFECTS. 



silent irM lAfoxvlcixi^, Simple in IVfE^vlipi^l^tiion. 



This apparatus lias been already installed by many of the chief workers in Electro-Therapeutics 

 in France and England, and is eivin? the very best results (ivV/,- leslimonials). 



Replaces large Indujtion Coils iq Laboratory aqd Research Work requiring 

 High Electric Tensions or Electric Oscillatioris of great power and uniformity. 



Descriptive Pamphlet gratis on application from the Sole Agents for Great Britain 



THE MEDICAL SUPPLY ASSOCIATION, 



228 Gray's Inn Road, London, \ 



where the apparatus 

 ) may be seen working. 



OI?.OSSSX^£:^V^'S GrA.^ e:]^.o-ii^£3S» 



RECENTLY 

 REMODELLED. 



Represents K and L 



types, giving 3'5 H.P. 



and 5 H.P. 



respectively. 



Immediate Delivery 



for Steele Sizes 



of Engines. 



CR.OSSH.E'V ^ROS. 



OREAT REDUCTION 

 GAS CONSUMED. 



Up to the end of 1904, 



over 50,000 eng-ines 



have been delivered, 



representing about 



three-quarters of a 



million actual 



horse-power. 



OF»E»ISH-A."W, aVi:.A.3VCHESTEK. 



]VEioi^.osoof>io o:Bj£3orrs. 



25 



NEW AND BEAUTIFUL PREPARATIONS 



Very fine Series illustrating the development 

 (Aspersi), 16 preparations in case ... 



Section through entire bud of Lily 



Beautiful Slides of Stephanoceros with cilia 



according to perfection 



Lophopus crystallinus 



Vermes (Marine), various 



Section of precious Opal, with main: 

 Sectioti of Quariz with fluid cavities 

 Leaf of Pampas Grass — very pretty section 

 For a Guinea a ypar yoi 

 NEW.- WATSON'S DIFFRACTION BUTTONS. A ^clenlific N 



apart are engraved. A beautifully soft ladiated appearance is imparted by these lines, the col 



■J-inch diameter, 4/6 each ; 6 in case for 25/- i-inch diam. 



Seid foi Watson's Illusirated Catalogues of Microscopes (No. 2J. Microscopic Obj' 



Po'^t free on applica 



/Established ~ 

 1837 



c (opaque) 



240 Mil 



. Slide 



W. WATSON & SONS, (' 



IN WATSON'S UNIQUE COLLECTION. 



Groups of Diatomaceai, Spicules, &c. A large variety at s. ,1. 



reduced prices ... ■ 8/6 to 25 



NEW Edition of Supplementary I ist of latest Micro. Objects 



now ready, post free. It gives full particulars of our beautiful 



series of Aquatic Organisms, &c., &c. 



Trypanosoma Brucei (Tsetse fly disease) 4 



Malarml pa.asites—miny phases each 3 6 



Radium for the Microscope. Mounted on a 3 x i slip as a 



MIlto. Object, snows scintillations strikir ely with low power 



Objective. Quite new ^ ' ... J ... 5 6 



from Watson & Sons' Cabinets. Send for particulars. 



buttons are made of polished steel upon which spiral lines ....A.^tb inch 



es. the colours being in the order of the Spectrum. Made in two sizes, 

 nch diameter, 2/6 each ; or 6 in case for 15/- 



(No. 3), Telescopes and Field Gl.isses (No. 6), 



Opticians to H.M. Government, 



313 MIGM HOLBORN^, LONDOl^J, ^SIV .C. 



-16 FORREST ROAD, EDINBURGH and 2 EASY ROW, BIRIVIINGHAM. .\wardetl 42 Oold and other Medals. 



THE CORRESPONDENTS' CAMERA. 



FOR HAND 

 OR TRIPOD. 



ladc -for the use of Newspaper Mer 



South Africa, and since used all over the World. 



T^lIIS Camera has been designed for the use of correspondents, 

 artists, and other travellers who, while requiring a Camera 

 po.ssessing the greatest stability, cannot spare the space for a regular 

 field camera in addition to a hand camera. It is made of the best 

 mahogany, carefully finished and covered wiih hard morocco 

 leather, or pnll.shed In naiural colour or ebonlsed at the same price. 

 It is admirably adapted for Telephoto work. Owin^ to 

 the use of wrood instead of metal, wherever possible, this 

 camera is lig;htcr than many of less substantial make. 

 EACH SIZE PERMITS OF THE USE OF THE SINGLE COMPONENTS OF A STIGMATIC OR OTHER CONVERTIBLE LENS 

 PRICE, including 3 Double Slides, but / 45 "y 3J. 5 by 4. 6i by 4• 



wlthotlt Lens or Shutter. \ £5 15s. 6ci. JSe lOs. Od. ST iSs ' Od 



a. H. DALLIVIEYER, Ltd., 25 NEWMAN ST., OXFORD ST., LONDON W 



MAKERS OF THE CELEBRATED DALLM EYE R LENSE S. ' 



printed by Richaki> Ci.av anii Sons, Li 



Ell, at - & S Ijread Street Hill, Queen ' 

 , l.ondon,W,C., and The Macmillan C 



luji, and published by Macmillan 

 TK.— Thuesuav, May 11,1905. 



