^506.^2. 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENXE. 



" To the solid ground 

 Of Nature trusts the mind which builds for aye."— Wordsworth. 



No. 1669, Vol. 64] 



THURSDAY, OCTOBER 24, 1901. 



[Price Sixpence. 



Registered as a Newspaper at the General Post Office.] 



[All Rights are Reserved. 



ELECTRIC LANTERN. 



A NEW 

 LENS 



FOR ALL 



WORK- 



.^NHHEIL 0^ 



^ J9 In 3 Series. vS» 



4^^ I. GKNf:RAL. O^. • 



*^jr II. CONVh-RTlBLE. ^D 



.>J III. SE-ECIAL PROCESS. , *rjk 



NEW PATTERN CHEAP ELECTRIC LANTERN, 

 fitted with Hand-feed Arc Lamp in Case, £10 10s. 



Wew Season's ua of Lanterns and Slides post free.' 



ly E "W T O MT WSC C5 O - , 



OPTICIANS, &e., TO THE KING, 

 3 FLEET STR EET. LONDON. 



X-RAY TUBES. 



Special arrangement 

 for the 



REGULATION OF THE 



HEAVY DISCHARGE 

 TUBES 



for use Hilh 



ELICTROLYTIC 

 BREAKS. 



Send for our 

 New Price List. 



JOHN J. GRIFFIN & SONS, Ltd., 



20-26 SARDINIA STREET, LINCOLN'S INN FIELDS, 

 LONDON, W.C. 



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



suitable for all work 



Fu/l Catalo^ie free on applicai:on ro the Manufacturers : — 



R. & J. beck:, iL.ta., 



68 CORNHILL, LONDON, E.C. 



SPECTAC LES 

 ELECTRIC LIGHT, INCANDESCENT GAS. 



And other Powerful Illuminants. 



NEGRETTI & ZAMBRA'S 

 THERMOSCOPIC LENSES 



P,,.t-i 1 111.- V.\.^ fnim r.lare, anJ 



BENDER THE LIGHT SOFT AND COOL 



N. and Z.s SPORTING SPECTACLES, close-fitting and having extra 

 large lenses, are the best for Shooting, Billiards, &c. 



ttlustrated Price Lists of Optical and Meteorological Instruments, 

 Free I'V Post to all /tarts of the U'orld. 



N EGRETTI and Z A M BRA, 

 38 HOLBORN VIADUCT, E.C. 



