























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



No. 2790, VoL. 111] | 


_ [PRICE ‘ONE SHILLING 



Registered as a Newspaper at the General Post Office.) 

SATURDAY, APRIL, 21, 1923, 

(All Rights Reserved. 











NEWTON'S « 
“DEMONSTRATOR'S” LANTERN 
For all classes of 
Projection Work. 
New Model) 
Price List sent on application. 
NEWTON & Co., 72 Wigmore St., London, W.1. 
(Specialists ia Optical Projection x aavatgia) 

BAIRD & TATLOCK(LOND 
SCIENTIFIC INSTRUMENT MANUFACTURERS 
and LABORATORY FURNISHERS. 
DIRECT 
READING 
EXPANSION 
APPARATUS 
Price 
£2 20 
WW Descriptive Circular 
post free. 
PHYSICAL APPARATUS OF ALL KINDS 
FOR COLLEGES AND SCHOOLS. 








REYNOLDS & BRANSON, Ltd. 
Complete Laboratory Furnishers and Manufacturers of Chemicals, 
Chemical, Physical, Optical, and Photographic Apparatus, 

 RYSTOS " MICROSCOPE LAMP can be supplied fitted for either electric 
globe or incandescent gas mz antle (if former, state voltage). PRICE COMPLETE 
with 2}” plano-convex c 
bayonet plug. The lamp 
ondensing lens with 6 feet of flexible cord and 
can be raised, lowered, or tilted to any required 
angle: £1: 10:0. 
Can be easily adapted as a Lecturer's Reading Lamp. 
144 COMMERCIAL STREET, LEEDS. 

STTTPUTTETTHAT OOOH ORUTTAARUOAUOVOUOD EMU OOOO LULCOOUUAOOUUO DOOD OUSIDE CCUM GUUPA Ee 
EGRETTI @ ZAMBRA 
38, HOLBORN VIADUCT.E.C.I. 
LONDON. 
Manufacturers of 
Meteorological Instruments 
to British and Foreign 
Governments. 
we, 
<p. 
