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A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

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



No. 2565, Vol. 102] THURS DAY, D E( K.MHER 2 6, 1918 



l as a Nfwspai^r at th<- r.eneral Poat Office 1 



[Price Ninepence. 



[All Rights Reserved 



BALANCES & WEIGHTS 



Graphite-Selenium Cells 



FOURNIBR 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 : — 



At 1 m.c. 

 At SO „ 

 At SOO „ 



) milliamp. 



1 



2 „ 



For particulars and prices apply to the Sole Agents : 



John J. Griffin & Sons, 



Makers of Physical and Electrical Apparatus, 



Kemble Street, KINGSWAY, 

 LONDON, W.C. 2 



CHEMICALS 



Analytical, Technical and Research. 



RECD. TRADE MARK APPARATUS 



Balances 



BENCHE S 



Fume Chambers, etc., 



for 



a snow crystal Chemical Laboratories 



Price Lists and Estimates on Application. 



REYNOLDS & BRANSON, LTD., 



Contractors to the War Office, Admiralty, and 

 Egyptian Government, &c, 



14 COMMERCIAL STREET, LEEDS. 



ACCURATE 



AND 



RELIABLE 

 THERMOMETERS. 



Send a note of your requirements 



to any of our addresses, and we 



will offer you the best types we 



have in stock. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT, E.C. 1 



LONDON. '" RE w\ E ? T ST - 



3*" Our City Branch h at 5 UaJcnhall Strict. EC. 3 



5 LEADENHALL ST 

 E.C. 3 



