A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

 Of Nature trusts the mind -which builds for ay:." — Wordsworth 



BROWNING'S ELECTRIC REGULATORS. 



Fig. 



Small ELECTRIC REGULATOR with ParabDlic Reflector (Fig. i). This Regulator will give a powerful and steadj' light, with from lo to 20 

 quart-size Grove s or Bunsea's Cells. Price ... ^ 



£2 5 



This Lamp woHcs well with from 20 to 30 pint Grove's Cells, or the same numl«r 



Parabolic Reflector, if required, extra 



Medium Size AUTOMATIC ELECTRIC REGLT-ATOR. 



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



Parabolic Reflector, extra ... ... ... ... ... ... ... ,„ ,.. ,,. __ ™ ™ "" 



Large Size AUTOMATIC REGULATOR. From 33 to 50 quart Grove's Cells, or the same number of 2 quart Bunsen's, should be used with 



this Lamp (Fig. 3). Pnce ... ... ... ... ... ... ... ... ... 



Parat>olic ReflectDr ... ... ... ... ... ... ... ... ... ... ... '_*' "' 



In these Regulators both carbons are moved by the electricit>- of the battery employed (without the aid of cloiikwork} Tthe light teaains un-J"jr^" 

 m height and more steady in action than any of the expensive regulators pre>-iously introduced. 



Ilh;stratkd Catalogue and Description of Spectroscopes sent for 7 St.^jips. 



2 15 

 6 



7 10 

 115 



JOH 



N BROWNING, 



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



ROYAL OBSERVATORY OF GREENNVICH, AND THE OBSERVATORIES OF KE\V, CAMBRIDGE, 



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



UNIVERSITIES, HOBOKEN COLLEGE, &c., &c. 



63, STRAND, T?V^.C. 



FACTORY— SOUTHAMPTON STREET, LONDON, W.C. ESTABLISHED loo YEARS. 



