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ral 
A WEEKLY ILLUSERATED JOURNAL OF SCIENCE. 
“ To the solid ground 
Of Nature trusts the mind which builds for aye.’ TT ORDER ORTH. 
No. 2799, VOL. 111] SATURDAY, JUNE 23, 1923 {PRICE ONE SHILLING 
Registered as a Newspaper at the General Post Office.) __ 2 cs =e x {All Rights ‘Reserved. 



BALANCES & WEICHTS. | REYNOLDS & BRANSON, Lro. 
Chemical and Physical Apparatus Makers to His ake s 
Government (Home and Overseas Dominions), 
Laboratory Outfitters, &c. 
BARR & STROUD LANTERN SLIDE APPARATUS. 
With graduated scales, which enable an operator, 
without calculation, or focussing on the screen, to 
obtain quickly a nega- 
tive of lantern size. 




Descriptive 
Circular 
and Prict 
on 
Application. 
With Incandescent Gas Burners, Adjustable Book 
Holder, one Double Dark Slide and Lens. 
Chemical, Glass, Porcelain, 
Nickel Ware, and Filter Papers. 
Apparatus in Glass, Metal, or Wood made 
%& ce to customers’ own Designs. 
F.E.BECKER ; s 
W. & J.GEORGE (LONDON) "8 PROPRIETORS CATALOGUES POST FREE. 
17 ro 29 HATTON WALL, LONDON.EC.|. Enquiries for Technical Chemicals in quantity solicited. 
14 COMMERCIAL STREET, LEEDS 

SPECTROMETERS 

GAUGES 
reading to -02” 
for the accurate 
measurement of 
small _ pressures. 
Particulars and Prices on application to— 
Quotations on request. 

JOHN J. GRIFFIN & SONS, LT. irs 
Kemble Street, Kingsway, NEGRETTI & ZAMBRA Saeko 
London, W.C.2. | 38 HOLBORN VIADUCT, E.C.1. 
LONDON. 

