








A WEEKLY ILLUSTRATED JOURNAL | OF SCIENCE. 
“* To the solid Mh or aye 
Of Nature trusts the mind which buil 
f for aye.” —WORDSWORTH. 



No. 2785, VOL. 111] SATURDAY, MARC MARCH 17, 1923 (Prick? E ONE. SHILLING 





Secauols ¢ weaare (HE REYNOLDS & BRANSON, Lro 
.E.BECKER & C° 
EORGE (LONDON) L’° PROPRIETORS 
Particulars and Prices on application to— 
JOHN J. GRIFFIN & SONS, LT. 
Kemble Street, Kingsway, 
London, W.C.2. 

Chemical Glassw: are, Chemical and Physical nbpaatn Makers 
to His Majesty's Government (Home and Overseas Dominions), 
Laboratory Outfitters, &c. 
Gel Medals at Allahabad and London. Grand Prix ets Gold Medal 
at the International Exhibition, Turin 
StROUD & SEMORL, SCIENCE LANTERN. 
; The ‘‘ University ’’ Lan- 
tern, with Russian iron 
body, sliding baseboard, two 
superior objectives, with rack 
and pinion for focussing, con- 
densers 4} in. diam., plane 
silvered mirror ‘‘ A," which is 
moved by a knob causing the 
rays to be reflected upwards 
for the projection of objects 
in a horizontal plane silvered 
prism which can be used at 
*C,” or as an erecting prism 
in mount “D,” (limelight 
ijmer or arc lamp, slide carrier, complete in travelling case, with reversible 
fidjustable stage for supporting apparatus. 
PRICE ON APPLICATION. 
Wireless Apparatus and Accessories supplied. 
CATALOGUES (Post Free). 
Optical Lanterns and Sree Apparatus. Chemical 
Apparatus and Chemicals (Ne dition), etc., etc. 

14 COMMERCIAL STREET, LEEDS, 
ee 
HUMIDITY 


RECORDING ASSMAN 
PSYCHROMETER 
with Ventilating Fan and Electric Motor. 
Write for full particulars. 
EGRETTI @ ZAMBRA 
38, HOLBORN VIADUCT E C1. 
LONDON. 
“Y 
