I 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solia ground 

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



No. 482, Vol. 19] 



THURSDAY, JANUARY 23, 1879 



[Price Sixpence 



Registered as a Newspaper at the General Post Office.] 



[.A.I1 Rights are Reserved. 



BROWNING'S ELECTRIC REGULATORS. 



Fig. 



Fig. 2. Fig. 3. ; 



Small ELECTRIC REGULATOR with ParaboUc Reflector (Fig. i). This Regulator will give a powerful and steady light, with from 10 to 20 



quart-size Grove's or Bunsen's Cells. Price ... 

 Small ELECTRIC REGULATOR, without Reflector (Fig. 2), for use in the Lantern, with adjustment for keeping the points of the burning 



carbons at one height, or separating them to aay required distance. This adjustment is indispensable for projecting the Spectra of Burning 



Metals on a Screen. With 20 quart-size Bunsen's Cells, this Regulator will illuminate a lo-feet disc. Price 

 Parabolic Reflector, if required, ext ra . .. ... ... ... ... ... ... ... ... „. 



Medium Size AUTOMATIC ELECTRIC REGULATOR. This Lamp works well with from 20 to 30 pint Grove's Cells, or the same number 



of quart Bunsen's (as Fig. 3). Price ... ... ... ... ... ... ... ... ... ... ... „. 



Parabolic Reflector, extra 



Large Size AUTOMATIC REGULATOR. From 95 to 50 quart Grove's Cells, or the same number of 2 quart Bunsen's, should be used with 



thie Lamp (Fig. 3). Price ... 

 Paracolic Reflector 



In these Regulators both carbons are moved by the electricity of the battery employed (without the aid of clockwork) ; the light remains uniform 

 in height and more steady in action than any of the expensive regulators previously introduced. 

 Illustrated Catalogue and Description op Spectroscopes sknt for 7 Stamps. 



£2 5 



2 15 

 6 



7 10 

 115 



JOHN BROWNING, 



OPTICAL AND 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, HOBOKEN COLLEGE, &c., &c. 



63, STRAND, W.C. 



FACTORY—SOUTHAMPTON STREET, LONDON, W.C. ESTABLISHED 100 YEARS- 



