


































= = == 





A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE, 
“ To the solid ground 
Of Nature trusts the mind which butlds for aye.” WORDSWORTH. 


No. 2788, VOL. 111] 
SATURDAY, APRIL 7, 1923 
[PRICE ONE SHILLING 





Registered as a Newspaper at the General Post Office.] 
(All Rights Reserved. 




NEWTON’S EPISCOPES 
for the projection of 
OPAQUE OBJECTS 
including 
MAPS, DRAWINGS, 
DIAGRAMS, PRINTED 
and TYPED MATTER, 
ILLUSTRATIONS, 
NATURAL OBJECTS, 
etc. 
Price list on application. 
(MODEL Cc.) 
Estab. over 
ay Mone King. NEWTON & CO. 200 years. 
Specialists in Optical Projection Apparatus for Visual Instruction, 
72 WIGMORE STREET, LONDON, W.1. 


= VITREOSIL ze) 
LABORATORY WARE 
Superior to Porcelain 
Constant in Weight 
Best Substitute for 
Platinum 
and more Economical 
ASK YOUR DEALER FOR IT 
GIVE IT A 
TRIAL 









SOLE MANUFACTURERS 
THE THERMAL SYNDICATE, LTD., 
VITREOSIL WORKS—WALLSEND-ON-TYNE,. 
LONDON DEPOT—28 we eS S.W.1. 

SCIENTIFIC INSTRUMENT MANUFACTURERS 
and LABORATORY FURNISHERS. 
DIRECT 
READING 
EXPANSION 
APPARATUS 
PHYSICAL APPARATUS OF ALL KINDS 
FOR COLLEGES AND SCHOOLS. 
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3 




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