A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

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



No. 2507, Vol. 102) 



THURSDAY, JANUARY 9. 1919 



[Price Ninepence. 



Registered as ;i Newspaper at the General Post Office.] 



[All Rights Reserved. 



BALANCES & WEIGHTS 



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 : — 



At 1 m.c. 

 At 50 „ 

 At 500 „ 



; milliamp. 

 2 



For particulars and prices apply to the Soi.k Agents : 



John J. Griffin & Sons, 



Makers of Physical and Electrical Apparatus, 



Kemble Street, KINGSWAY, 

 LONDON, W.C. 2 



CHEMICALS 



Analytical, Technical and Research. 



RECDT ™ 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. 



T^EGRETTI &, ZAMBRA, 

 38 HOLBORN VIADUCT, E.C. 1 



S LEADENHALL ST. LONDON '" RE0ENT ST - 



a* - Our G/J Branch is at 5 Lcadcnhall Strict. EC. 3 



