PeOVEEKLY [ILLUSTRATED JOURNAL OF SCIENCE. 
: *©To the solid ground 
OF Nature trusts the mind which builds for aye.”—Worpsworru 
No. 1435, VOL. 55] 
THURSDAY, APRIL 29, 1897. 
[PRICE SIXPENCE 
_ Registered asa Newspaper at the General Post Oficed) 
INDUCTION COILS. 
APPS’ PATENTED INDUCTION COILS are now manufactured 
concurrently by 
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“xX” RAY “FOCUS” 
TUBES, 25s. 
FLUORESCENT SCREENS, 68s. and 90s. 
Complete Apparatus for Réntgen ‘‘ X’’ Rays, with Coils 
and Fluorescent Screens, &c. | 
HiGremMeGtnATITY ONLY. 
Detaled List o. 
HEAT INDICATING SCREENS. 
The Double IODIDE for preparing the above, 
9/6 per 02. | 
INVALUABLE TO LECTURERS AND SCIENCE 
DEMONSTRATORS. | 
WRITE FOR PARTICULARS AND INSTRUCTIONS, and 
also for CATALOGUE of 
X-RAY APPARATUS, 
-- ~~ INCLUDING 
INDUCTION COILS. TESLA COILS, 
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WIMSHURST MACHINES, 
WC. XC. 
Tication. 
ALL KINDS. OF PHYSICAL AND CHEMICAL 
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JOHN. J. GRIFFIN & SONS, FE 
22 GARRICK STREET, LONDON, W.C. 
_BAROGRAPHS pel Baas Wi | 
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THE Dyes, iyoner, Co. “Ware Snesase ors to 
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D'ARSONVAL GALVANOMETER 
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ON EGRETTI AN D ZAMBRA’S 
The Barograph is fitted in a Mahogany Case with Glass Front, as shown 
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NEGRETTI & ZAMBRA, 
SCIENTIFIC INSTRUMENT MAKERS to the QUEEN, 
38 HOLBORN VIADUCT, E.C. 
Branches: 45 CORNHILL, and 122 REGENT STREET. 
