A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

 Of Nature trusts the mind which builds for aye." — Wordsworth 



No. 499, Vol. 20] 



THURSDAY, MAY 22, 1879 



[Price Sixpence 



Registered ax a Newspaper at the General Post Office.] 



[All Rights are Reserved. 



BROWNING'S 



PLATYSCOPIC LENS. 



Engraved Real Si,i.. 

 A NEW ACHROMATIC COMBINATION, 



COMBINING THE DEFINITION OF A MICROSCOPE WITH THE 

 PORTABILITY OF A POCKET LENS. 



The Platyscopic I^ns is invaluable to botanisb;, mineralogists, 

 or entomologists, as it focnsses 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 three degrees of power, 

 magnifying respectively I J, 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 Tortoise- 

 shell Frames. 



Price of the Platyscopic Lens, mounted in Torloiseshell, magni- 

 fying either 15, 20, or 30 diameters, £1 ^s. 



Illustrated description sent free. 



BROWNING'S 



POCKET MICROSCOPE. 



The New Pocket or Field Microscope, on Firm 

 Folding Brass Tripod Stand, with fine Adjustment, 

 i-inch Objective, Large Field Eye-piece, Hand-pliers, 

 &c. ; height when set up, 10 inches ; dimensions, packed 

 in Morocco Case, 5 i inches long. Price ^i lis. 6./. 



Or with i-inch and 2-inch Objectives, Stage, Forceps 

 Stage Plate, and Dipping Tube, £2 2s. 



List of Microscopes sent free. 



Illustrated Catalogue of Microscopes, with 35 Illustra- 

 tions, 8 whole page Illustrations, sent for Six Stamps. 



JOHN BROWNING, 



OPTICAL AND PHYSICAL INSTRUMENT MAKER TO H.M. GOVERNMENT, THE ROYAL SOCIETY, 

 THE ROYAL OBSERVATORIES OF GREENWICH AND EDINBURGH, &c., &c. 



6 3, STRAND, W.C, LONDON. 



FACTORY— SOUTHAMPTON STREET and EXETER STREET, LONDON. 

 PRIZE MEDAL, 1862. Telescopes, Spectroscopes, Opera Claues, ^c, Sfc. ESTABLISHED 100 YEARS. 



