AeVVIDEKIGYs HebG Sie wA rE Dj OURNATE Oks 
SCIENCE: 
“* To the solid ground 
Of Nature trusts the mind which builds for aye.” 
—WorpSWoRTH. 
No. 1428, VOL. 55] THURSDAY, 
MARCH 11, 
1897. [PRICE SIXPENCE. 
Registered as a Newspaper at the General Post Office.] 
{All Rights are Reserved. 
Sa e RN SLIDES 
NANSEN'S | POLAR EXPEDITION 
NEWTON & CO., ov 3 FLEET STREET, E.C., 
Have obtained the sole right to manufacture and sell Lantern 
Slides of Dr. NaNSEN’s Pictures in 
TPA iEST NORTH.” 
Price 25. each. List post free. 
The Slides are printed from the same Negatives as those 
used by Dr. Nansen at his own Lectures, which were made 
for him by Newron & Co. 
As the demand for these will probably be large, early 
application is advisable. 
“A series of singularly beautiful photographic illustra- 
tions.” — The gene, February 9, 1897. 
-BECK’S MICROSCOPES. 
1-in. and }-in. Object Glasses, 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£6 10s. _ 
No. 258.—THIS MODEL, with 
3-in. and 
Two Eyepieces, and packed 
in Polished Mahogany Case, 
£7 5s. 
No. 298.—The addition of Abbe 
Condenser to 258 with Iris 
Diaphragm and _ Focussing 
and Swinging Adjustments, 
£8 lds. 
FULL PARTICULARS FREE on APPLICATION to 
R. & J, BECK, LTD., 68 CORNHILL, LONDON, £.¢. 
STAND No. 25. 
No. 25A. —THIS MODEL, with | 
j-in. Object Glasses, | 
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- 
me ologists, as it focuses about three times as far from the object as the 
oddington Lenses. This allows opaque objects to be ex: amined easily. 
The Platyscopic Lens is made of four degrees of power, m agnifying 
respectively to, 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, magnt- 
fying either 10, 15, 20, or 30 diameters, 18s. 6a. each power. 
Illustrated description sent free. 
JOHN BROWNING, 63 STRAND. LONDON, W.C. 
NEGRETTI AND ZAMBRA’S 
BAROGRAPHS AND _THERMOGRAPHS. 
The Bee is fitted in a Mahogany Case with Glass Front, as shown 
above The Ther. .4raph is mounted in a japanned Metal Case with Glass 
Front, for either indvor or outdvor 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 QUEEN, 
38 HOLBORN VIADUCT, E.C, 
Branches—45 CORNHILL, and 122 REGENT STREET. 
t 
