A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" 't'o the solid p-onnd 

 Of Naiioe triisn the mind wliich builds for aye." — WoKl swoKTll. 



No. 1653, Vol. 64] 



THURSDAY, JULY 4. 1901. 



[Price Sixpenxe. 



■.Re^tered as a Newspaper at the General Post Office.) 



[All Rights are Reserved. 



T^A^TtCr-Bl 



DEMONSTRATION BALANCE 



' PHYSICAL 

 EXPERIMENTS. 



Specially designed to 

 show the principles under- 

 lying the construction of 

 tlie Balance. 



£7:7:0 



FULL PARTICULARS ON 

 APPLICATION. 



JOHN J. GRIFFIN & SONS, ]2 



20-26 SARDINIA ST., LINCOLN'S INN, W.C. 



A NEW 

 LENS 



^ig^HEIL O/f^ 



tOR ALL 

 WORK. 



^^ II. CO.NVh,KTIBLE. 



.^W III. SEECIAL PROCESS. 



In 3 Srries. 

 I. GENERAL. 



^ 



% 



This rapid, wide, medium or narrow angle lens all in one is 



suitable for all work. 



Full Catalo^te free on application lo the Manufacturers : — 



R. «& J. BECK, Ltd., 



68 CORNHILL, LONDON, E.G. 



NEGRETTI & ZAMBRA'S 



IMPROVED 



SELF-RECORDING RAIN- 



CAUCES, BAROMETERS & 



THERMOMETERS, 



Giving continuous Records 



on Charts which only require 



changing weeiily. 



Invaluable to Invalids and 



others unable to take daily 



readings. 



Illustrated Price List of Instruments free by Post to all 

 parts of the World, 



NEGRETTI & ZAWIBRA, 

 38 HOLBORN VIADUCT, E.G. 



Branches: 4; CORNHILL. and ,22 REGENT STREET. 

 AWARDED TWO GOLD MEDALS PARIS EXHIBITION 1900 



