A WEEKLY ILLUSTRATED JOURNAL OF'STIENCE. 



"To the solid ground 

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



=rf£?= 



No. 2549, Vol. 102] THURSDAY, SEPTEMBER 5, 1918 



I Price Sixfkncl 



Registered as a Newspaper at the General Tost Office.] 



[ All K ights Reserved. 



BALANCES &WEIGHTS 



Braphite-Seleniysn 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. 

 1 » 



2 



For particulars and prices apply to the Sole Agents : 



John J. Griffin & Sons, 



Makers of Physical and Electrical Apparatus, 



Kemble Street, K1NGSWAY, 

 LONDON, W.C. 2 



A>X BASINS, BEAKERS, BOATS, 

 ^^\ CAPSULES, CONDENSERS, 

 " < 5£\ CRUCIBLES, ' FLASKS, 



We 



specialise 

 in the manu 

 facture of 

 apparatus to cus 

 toraers' own designs 



List and sample free on 



application to 



THE SILICA SYNDICATE, Ltd., 



RETORTS, 



TRIANGLES, 



TEST-TUBES, 



TUBING, 



^v\ ETC. 



28 VICTORIA STREET, V*y« 



K 



Telephone : Holborn 



WESTMINSTER, S.W.I 



!o. V Note Ncm Add 



<P 



ANEMOMETRY. 



NEGRETTI &, ZAMBRA, 

 38 HOLBORN VIADUCT, E.C. 1 



<5 CORNHILL LONDON. -"REOENTST 



