









A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE, 
“* To the solid ground 
Of Nature trusts the mind which builds for aye. —— ORDSWORTH. 




No. 2784, VoL. 111] SATURDAY, 
MARC I 1 10, 

1923 [PRICE ONE SHILLING 


Registered as a Newspaper at the Genera <1 Post Office. is 
~ [All Rights Reserved. _ 



NEWTON’S 
Model D 
EPISCOPE 
for the projection of 
OPAQUE OBJECTS 
including 
MAPS, DRAWINGS, 
DIAGRAMS, PRINTED 
and TYPED MATTER, 
ILLUSTRATIONS, 
NATURAL OBJECTS, 
etc. 
NEWTON'S 
EPISCOPE 
Mooe. D 
Price 
£31 10 0 
Estab. over 
HM. the King, NEWTON & CO. 200 years. 
Specialists in Optical Projection Apparatus, 
72 WIGMORE STREET, LONDON, W.1. 










SCIENTIFIC INSTRUMENT MANUFACTURERS 
and LABORATORY FURNISHERS. 
DIRECT 
READING 
EXPANSION 
APPARATUS 
y Descriptive Circular 
post free. 
PHYSICAL APPARATUS OF ALL KINDS 
FOR COLLEGES AND SCHOOLS. 
5 CROSS STREET HATTON GARDEN LONDON ECIY A 














CHEMICALS 
Analytical, Technical and A.R. 
RECD, TRADE MARK A P PARAT U S 
Balances 
BENCHES 
Fume Chambers, etc., 
f 


or 
Chemical, Physical, and 
A SNOW CRYSTAL Technical Laboratories. 
Price Lists and Estimates on Application. 
Wireless Apparatus and Accessories supplied. 
Also New Catalogues of Chemical Apparatus aad Chemicals. 
REYNOLDS & BRANSON, LTD., 
Contractors to the War Office, Admiralty and 
Egyptian Government, &c. 
14 COMMERCIAL STREET, LEEDS. 


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