A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



"To the solid ground 

 Cf Nature trusts the mind which builds for aye." — WORDSWORTH 



No. 520, Vol. 20] 



THURSDAY, OCTOBER 16, 1879 



[Price Sixpence 



Registered as a Newspaper at the General Post Office.] 



[All Rights are Reserved. 



BROWNING'S SPECTROSCOPES. 



SCREEN SPECTRUM APPARATUS. 



Improved Electric Camera, with 4^ inch condensers, the 

 body of brass, bronzed, with two nozzles specially arranged 

 for exhibiting spectra or diagrams on the same screen, 

 without shifting the lantern or re-arranging the apparatus. 

 Large size Electric Regulator for the above, to work with 

 from 25 to 50 Grove's or Bunsen's cells. Two extra-sized 

 Bisulphide of Carbon Prisms. Prism Stand and Cover, 

 adjustable for height with clamp motions. Large Con- 

 densing Lens on Brass Stand, adjustable for height. 

 Revolving Diaphragm. Rotating Carbon Holder. Maho- 

 gany Case containing set of metals and salts for burning 

 in the Electric Arc, with carbon crucibles, pliers, and 6 feet 

 of carbon rods, &c., for the large regulator. Battery of 

 40 quart Bunsen's Cells in four varnished Oak Trays. 



I Price of the Set of Apparatus Complete . . £50 



BROWNING'S New Lantern Microscope 



adapted for the above J65 10 



Illustrated Catalogue of Spectroscopes, Price 6if. 



HOW TO WORK WITH THE SPECTROSCOPE. B>- JOHN 

 BROWNING. Price is. 6d. 



LIS TS OF PRICES SENT FR EE. 



JOHN BROWNING, 



OPTICAL AJS'D PHYSICAL INSTRUMENT MAKER TO H.M. GOVERNMENT, THE ROYAL SOCIETY, THE 



ROYAL OBSERVATORY OF GREENWICH, AND THE OBSERVATORIES OF KEW, CAMBRIDGE, 



MELBOURNE, THE U.S. NAVAL OBSERVATORY, CAMBRIDGE AND HARVARD 



UNIVERSITIES, HOHOKEN COLLEGE, &c., &c. 



63, STRAND, W.C. 



FACTORY— SOUTHAMPTON STREET, LONDON, W.C. 



