y 



\ WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye." — Wordsworth. 



No. 2551, Vol. 102I 



Registered .- neral Pf>st Office I 



THURSDAY, SEPTEMBER 19. 1918 



[Price Sixpence. 



(All Rights Reserved. 



Graphite-Selenium Cells 



FOURNIER D'ALBE'S PATTERN. 



Great Stability and High Efficiency. 



With a sensitive Se surface of 5 sq. cm. and a voltage 20 the 

 additional current obtainable at various illuminations (in 

 metre-candles) is : — 



For particulars and prices apply to tbe Soi.f. Agents : 



John J. Griffin & Sons, 



Makers of Physical and Electrical Apparatus, 



Kemble Street, KINGSWAY, 

 LONDON, W.C. 2 



REYNOLDS & BRANSON, Ltd., 



Chemical and Scientific Instrument Makers to His Majesty's 



Government (Home and Overseas Dominions). 



LABORATORY FURNISHERS and MANUFACTURING CHEMISTS. 



WORKS AND OTHER 



LABORATORIES 



equipped 



with Benches, Fume 



Chambers, Apparatus 



and Chemicals. 



Designs and quotations 

 submitted on application 



BRITISH ■ MADE Glass, Porcelain, 



Nickel Ware, and Filter Papers. 



Apparatus in Glass, Metal, or Wood made 



to customers' own Designs. 



CATALOG VMS J'OST FREE. 

 Enquiries for Technical Chemicals in quantity solicited. 



14 COMMERCIAL STREET, LEEDS. 

 ANEMOMETRY. 



The Combined Anemo-Biuirraph 

 and Wind - Direction Recorder. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. E.C. 1 



LONDON. 



COKNHILL 

 I .C. 3 



