October 5, 1905 J 



NA TURE 



W. WILSON, 



Maker of 



SPECTROSCOPES, SPECTROMETERS, 



GONIOMETERS, 



OPTICAL BENCHES, OPTICAL AND OTHER 



MEASURING INSTRUMENTS. 



BEST WORK. MODERATE PRICES. 



NEW 

 X-RAY PLATE. 



Price List Free. 



I Belmont Street, Chalk Farm, London, N.W. 



GLEW'S SCINTILLOSCOPE 



Show 



(P; 



a magnificent display ot scintillations, 

 showers of sparks, direct from the mineral Pitch- 

 blende, Radium, Polonium, Uranium, Thorium, or 

 any radio-active substance, even a Welsbach mantle 

 contains sufficient Thorium to excite the very sensi- 

 tive screen of the Scintilloscope, which is far more 

 sensitive than the Spinthariscope. The Scintil- 

 loscope rivals the most delicate Electroscope as a 

 'of Alpha ra 



The eye 



tible show 



of > 



of 



: producing th 



white light, giving a very realistic idea of tht 

 less activity of these marvellous substances which 

 ■ific bombardment causing this beautiful display. 

 Mm- See Nature, September 29, page 535. 

 Glew's Scintilloscope Superior Lens, with Extra-sensitive Pitchblende and 

 Polonium Screens, giving brilliant effects, Complete, ys. 6d., Post free, 

 U.K. Foreign Postage extri, weight 2 ounces. 

 Pieces of Pitchblende mineral, ground flat and polished, with Sensitive 

 Screen attached, for use in Scintilloscope or with any strong pocket 

 magnifier, from 75. 6i{. each, according to size. 

 Radio-active supplies of every description, on Sale or Hire. Radium 

 Bromide 1,800,000 units on hire for lectures. 



F. HARRISON GLEW, Radiographer (Silver Medallist, Paris, 1900), 

 156 Clapham Road, London, S.W. 



THE 



SANGER-SHEPHERD 



X RAY PLATE 



is undoubtedly the best plate at present 

 on the market. 



Its advantages are : — 



(i) Great sensitiveness to .X-Rays, thereby lessening 

 exposure. 



(2) As the result of shortened exposure enormously in- 



creased detail of structure shown in the developed 

 plate. 



(3) The emulsion is in a single thin film, which does not 



frill and reduces by half the time usually taken to 

 develop and fix. 



Already in use at the principal London Hospitals. 



Piices of standard size=, 

 10x8 i2,<io 15x12 



12/6 17/6 30/- per doz. 



Pamphlet, including Developers, &b., free on application to 



tt)e AGENTS FOR THE SALE OF THIS PLATE— 



HARFSY W. cox;, IL,t<t., 



ACTUAL MAKERS of X-Ray, &c., Apparatus to the Admiralty, 

 War Office, Colonial ORice, Indian Government, &c., 



la ROSEBERY AVENUE, & 15-21 LAYSTALL ST., LONDON, E.G. 



VOQEL'S 

 SPECTROGRAPH. 



Two prisms of dense flint-glass enclosed 

 in a strong brass case, to which the colli- 

 mator and the camera are attached ; 

 colliinator of tiin. aperture and iSin. focal 

 length, with adjustable slit with micrometer- 

 screw and dividing drum ; the camera is 

 furnished with an achromatic double 

 objective of 2in. aperture and 29in. focal 

 length ; size of plate, /^in. by 5in. 



Can 1)6 seen at my Slwwrooms 

 as 1)6 low- 



DELIVERY FROM STOCK. 



PETER HEELE, 



115 HIGH HOLBORN, 



LONDON, W.C. 



Maker of Physical, Chemical, and 

 other Instruments, and every kind of 



Spectroscope and Polarimeters. 

 GRAND PRI.X, PARI5, 1900; ST. LOUIS, 1904. 



Telegrams: ••ARCTITUDE. LONDON." 



