A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 
ee “To the solid ground 
Of Nature trusts the mind which buzlds for aye.”—WordswortH 
No. 1433, VOL. 55] 
THURSDAY, APRIL 15, 1807. 
[PRICE SIXPENCE. 
concurrently by 
NEWTON & CO., 3 FLEET STREET, LONDON. 
oh eae 
Sa 
ae 
FLUORESCENT SCREENS, 63s. and 90s. 
Complete Apparatus for Réntgen ‘“‘ X”’ Rays, with Coils 
and Fluorescent Screens, &c. | 
Hicks t QUALITY ONLY. 
Detatled List on Application. 
HEAT INDICATING SCREENS. 
The Double IODIDE for preparing the above, 
9/6 per 02. 
TO LECTURERS AND SCIENCE | 
DEMONSTRATORS. 
WRITE FOR PARTICULARS AND INSTRUCTIONS, and 
also for CATALOGUE of : | 
X-RAY APPARATUS, 
“INCLUDING 
INDUCTION COILS, TESLA COILS, 
TUBES, SCREENS, BATTERIES, 
WIMSHURST MACHINES, 
&c., &c. 
INVALUABLE 
ALL KINDS OF PHYSICAL AND CHEMICAL 
APPARATUS manufactured by 
JOHN J. GRIFFIN & SONS, E 
22 GARRICK STREET, LONDON, W.C. 
16 RED LION ST 
Bees [All Rights are Reserved. 
NALDER BROS. & CO. 
aes 
AYRTON-MATHER UNIVERSAL SHUNT BOX. 
Does not need adjusting for each Instrument, but can be used indis- 
oriminately for Galvanometers of any resistance. No plugs ronmersloces 
Multiplying powers -—1, 3, 10, 30, 100, 300, 1000. a Ss 
This Instrument also makes a convenient form of Potentiometer. 
» Price £3 15s. 
WRITE FOR CATALOGUE. Cable Address, “SEcoHmM, Lonpon.” 
No Agents, U.S-A. This Instrument delivered anywhere in U.S.A. for $24, 
NEGRETTI AND ZAMBRA’S 
BAROGRAPHS AND THERMOGRAPHS. 
The Barograph is fitted in a Mahogany Case with Glass Front, as shown 
above. The Thermograph is mounted in a japanned Metal Case with Glass 
Front, for either indoor or outdoor use. The above give continuous records 
on Charts, which only require changing once a week, and are invaluable to 
invalids and others who are unable to take daily readings of the ordinary 
instruments. Price of each, with supply of Charts for one year, £6 10s. 
NEGRETTI & ZAMBRA, 
SCIENTIFIC INSTRUMENT MAKERS to the QUHEN 
38 HOLBORN VIADUCT, E.C. 
Branches: 45 CORNHILL, and 122 REGENT STREET. 
REET, LONDON, E.C. 
