A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 
“To the solid ground 
Of Nature trusts the mind which builds for aye.”—WorDSWoRTH. 
No. 1432, VOL. 55] 
THURSDAY, APRIL 8, 1897. 
[PRICE SIXP ENCE. 
Registéred as a Newspaper at the General Post Office.] 
INDUCTION COILS. 
APPS’ PATENTED INDUCTION COILS are now manufactured 
eoncurrently by 
NEWTON & CO., 3 FLEET STREET, LONDON. | 
f encnm 
“xX” RAY ‘*FOCUS” 
FLUORESCENT SCREENS, 68s. and 90s. 
Complete Apparatus for Réntgen ‘‘X”’ Rays, with Coils 
and Fluorescent Screens, &c. 
HIGHES® (QUALITY ONLY: 
Detailed List on Application. 
BECK’S MICROSCOPES. 
No. 25.—THIS MODEL, with 
r-in. and 4-in. Object Glasses, 
in Polished Mahogany Case, 
£6 10s. 
.—THIS MODEL, with 
.and }-in. Object Glasses, 
3- 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£7 5s. 
No. 298.—The addition of Abbe 
Condenser to 258 with Iris 
Diaphragm 
and Swinging Adjustments, 
£8 15s. 
and_ Focussing 
STAND No. 25. 
FULL PARTICULARS FREE on APPLICATION to 
RB. & J. BECK, LTD., 68 CORNHILL, LONDON, £.C. 
Two Eyepieces, and packed | 
{All Rights are Reserved. 
BROWNINGS 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 off 
Nature ought to-do).”"—GranT-ALLEN in Anow/ledge. 
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 Tortotseshell, magni= 
fying etther 10, 15, 20, or 30 dzamelers, 18s. 6d. each power. 
Illustrated description sent free. 
JOHN BROWNING, 63 STRAND. LONDON, W.C. 
| NEGRETTI AND ZAMBRA’S 
BAROGRAPHS A 
aph is fitted in a Mahogany with Glass Front, as shown 
Thermograph is mounted in a japanned Metal Case with Glass 
either indoor or outdoor use. The above give continuous records 
, which only require changing once a week, and are invaluable to 
nd 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 QUEEN, 
38 HOLBORN VIADUCT, E.C. 
Branches : 45 CORNHILL, and 122 REGENT STREET. 
