Y (We — ri i 































1922 
A WEEKLY ILLUSTRATED JOURNAL OF sQIENCE, 
© To the solid ground . Pe 
Nea 2 A.cal 
~2 0 nal. Nas? 
——————— 
[PRICE ONE SHILLING 
[All Rights Reserved. 
=]| REYNOLDS & BRANSON, Lro. 
Chemical Glassware, Chemical and Physical ial Be Makers 
to His Majesty’s Government is ome and Overseas Dominions), 
Laboratory Outfitters, &c. 
Gold Medals at Allahabad and London. Grand Prix and Gold Medal 
at the International Exhibition, Turin. 
STROUD & RENDELL SCIENCE LANTERN. 
The ‘‘ University ’’ Lan- 
tern, with Russian iron 
body, sliding baseboard, two 
Of Nature trusts the mind which builds for aye.” —WORDSWORTH. 
No. 2800, VOL. 111] SATURDAY, JUNE 30, 1923 
Registered as a Newspaper at the General Post Office.] 











oY TONS EPISCOPES 
for the projection of 
OPAQUE OBJECTS 
including 
MAPS, DRAWINGS, 

(MODEL Cc.) 
we ticians to 
tne king NEWTON & CO. 
DIAGRAMS, PRINTED 
and TYPED MATTER, 
ILLUSTRATIONS, 
NATURAL OBJECTS, 
etc. 
Price list on application. 
Estab. over 
200 years. 
teste in Optical Projection Apparatus for Visual Instruction, 
72 WIGMORE STREET, LONDON, W.1. 

superior objectives, with rack 
and pinion for focussing, con- 
densers 44 in. diam. » plane 
silvered mirror ‘‘ A,” which is 
moved bya 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 
burner or arc lamp, slide carrier, complete in travelling case, with reversible 
adjustable stage for supporting apparatus. 
PRICE ON APPLICATION. 
Wireless Apparatus and Accessories supplied. 
CATALOGUES (Post Free). 
Optical Lanterns and Accessory Apparatus. Chemical 
Apparatus and Chemicals, etc., etc. 

14 COMMERCIAL STREET, LEEDS. 

SCIENTIFIC INSTRUMENT MANUFACTURERS 
and LABORATORY FURNISHERS. 
STANDARD GATALOCUES 
Vol. I. CHEMISTRY. 
Vol. II. PHYSIOLOGY. 
Vol. III. BIOLOGICAL SCIENCES— 
including Anatomy, Embryology, 
Zoology, 
Microscopy, Histology, 
Bacteriology, Protozoology, Patho- 
logy, Hygiene, Agriculture, etc. 
Vol. [V. PHYSICS. 

GAUGES 
reading to -02” 
for the accurate 
measurement of 
small _ pressures. 
Quotations on request, 
NEGRETTI & ZAMBRA <a8% 
38 HOLBORN VIADUCT, E.C.I. 
LONDON. 

