A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 
“To the solid ground 
Of Nature trusts the mind which builds for aye."—WoRDSWORTH. 
No. 2461, VOL. 98] 
THURSDAY, DECEMBER 28, 1916 
[ PRicE SIXPENCE. 
ees as a Newspaper at the General Post Office.) 
{All _Kights Reserved. 
BUY DIRECT FROM 
F.E.BECKER & CO, HATTON WALL, 
LONDON, E.C. 
(W.&J.GEORGE. LTD.,SUCC) 
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.. ... 
Ati bOs 55 
At 500 ,, 
} milliamp. 
N= 
For particulars and prices apply to the SOLE AGENTs : 
John J. Griffin & Sons, 
Makers of Physical and Electrical Apparatus, 
Kemble Street. KINGSWAY, 
LONDON, wW.C. 
REYNOLDS & BRANSON, Ltd. 
= “RYSTOS” STILL. 
Improved Central Fiue Water Sti.l and Condenser. 
In this pattern the heat is conducted through the water by means ofta 
central tubé ensuring economy of heating, The condenser worm is of 
pure tin, and the water jacket is air-cooled on two surfaces. tee gallon 
size (r litre distilled water per SEHK solid copper . £3 
Ring Burner for same . oe os 7 6 
Catalogues Post Free. 
14 Commercial Street, Leeds. 
A New Barograph—THE * JORDAN.” 
(Regd. Design 62871.) 
Shows at a glance the movements_of the barometer during 
the preceding days. 
Descriptive Leaflet post fiee on-application to 
NEGRETTI & ZAMBRA, 
38 HOLBORN VIADUCT, E.C.; 
45 CORNBILL, E.C.; 122 REGENT ST., W. 
