—— 
A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE, 
“© To the solid ground 
Of Nature trusts the mind which builds for aye.” —WORDSWORTH. 
No. 1562, VOL. 60] 
THURSDAY, OCTOBER 5, 1899. 
[PRICE SIXPENCE. 
Registered as a Newspaper at the General Post Office.] 
(All Rights are Reserved. 
IRELESS TELEGRAPHY. 
SS 
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LONGON 
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‘6 
THE “APPS-NEWTON” INDUCTION COILS 
made entirely in the London Workshops of 
NEVTON & CoO., 
3 FLEET STREET, E.C., 
are now used by all the principal experts in Wireless 
Telegraphy, as well as in Radiography. 
BEC K’S | 
NEW 
MICROSCOPE 
THE 
“BRITISH STUDENTS.” 42a 
Microscope Stand No. 55, as 
igured, with Iris Diaphragm, 
Ine Eye-piece; Double Nose- 
jiece, Two Object-glasses, 2/3” 
nd 1/6’, adjusted to be in 
yhout focus, and the whole 
yacked in polished Mahogany 
. £6:8:6 
No. 55- 
R. & J. BECK, Ltd., 
68 CORNHILL. LONDON. E.C,. 
BROWNING’S PLATYSCOPIC LENS. 
With Larger Angles, Increased Field, and Improved Definition 
Engraved Real Size. 
AN ACHROMATIC COMBINATION, 
COMBINING THE DEFINITION OF A MICROSCOPE WITH THE 
PORTABILITY OF A POCKET LENS. 
“Tf you carry a small Platyscopic Pocket Lens (which every observer of 
Nature ought to do).”—GranT ALLEN in Knowledge. 
The Platyscopic Lens is invaluable to botanists, mineralogists, or ento 
| mologists, as it focuses about three times as far from the object as the 
Coddington Lenses. This allows opaque objects to be examined easily. 
The Platyscopic Lens is made of four degrees of power, magnifying 
respectively 10, 15, 20, and 30 diams. ; the lowest power, having the largest 
field, is the best adapted for general use. 
The Lenses are set in Ebonite Cells, and mounted in Tortoiseshell Frames. 
| Price of the Platyscopic Lens, mounted in Tortoiseshell, magnifying either 
10, 15, 20, 0” 30 diameters, each power, 15s. 
In nickelised German Silver, cach power, 17s. 6d. 
Illustrated Description sent free. 
JOHN BROWNING, 63 STRAND, LONDON, W.C. 
SPECTACLES 
ELECTRIC LIGHT, INCANDESCENT GAS, 
And other Powerful Illuminants. 
NEGRETTI & ZAMBRA’S 
THERMOSCOPIC LENSES 
Protect the Eyes from Glare, and 
RENDER THE LIGHT SOFT AND COOL. 
Illustrated Price Lists of Optical and Meteorological Insty.oréuts 
Free by Post to all parts of the World. 
NEGRETTI AND ZAMBRA, 
SCIENTIFIC INSTRUMENT MAKERS to tHE QUEEN, 
38 HOLBORN VIADUCT, E.C. 
BRANCHES : 46 CORNHILL; 122 REGENT STREET. 
