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IMPROVED SPECTRUM APPARATUS. 
JOHN BROWNING begs to call the attention of the scientific public to the fact that he 
has re-modelled and greatly improved nearly the whole of his specialities in Spectroscopes 
within the last year; more particularly he would mention his MINIATURE SPECTROSCOPE, the 
Direct-Viston SPECTROSCOPE, with Micrometric Measuring-Apparatus, and his UNivERSAL 
Automatic Spectroscope. JOHN BROWNING can now supply one of these instruments 
with a dispersive power equal to eleven flint-glass prisms, and so compac¢t that it can be easily 
adapted to a 4-inch Refracting Telescope. 
COLONEL CAMPBELL’S NEW SPECTROMETER. 
By the aid of this contrivance an unskilled observer can map any spectra without taking readings. 
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NS a RS ge hel og a i 8 
Optical and Physical Instrument Maker to the Royal Observatory, &c., &c., 
63, Strand, W.C., and 111, Minories, London, E. 
ESTABLISHED I00 YEARS. 
An Illustrated Descriptive Ca-alogue of Spectroscopes, 18 Stamps. List of Spectroscopes 
Free by Post. 
BROWNING’S 
NEW LARGE AUTOMATIC ELECTRIC LAMP. 
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In this Lamp both carbons are moved by the elec- 
tricity 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 regu- 
lators previously introduced. Any number, from 20 
to 50-quart Grove's Cells, or 2-quart Bunsen’s, may 
be used with this Lamp. Price £8 8s. 
Joun BrowninG begs to announce that he has 
prepared, with peculiar care, a great number of Dia- 
grams to illustrate recent discoveries in Spectrum 
Analysis and other branches of Observational 
Astronomy. These Slides can be had either plain or 
exquisitely coloured. Prices—3s. 6d. plain, and from 
4s. 6d. to tos. 6d. coloured. A list of subjeéts priced 
on application. 
Photographs of Microscopie Objects for the Lantern, 
3s. each. Lists on application. 
Ecectric Lamps, either separately or with Lan- 
tern Apparatus, for Public Exhibitions and Lectures. 
for showing Diagrams or Spectrum Experiments on 
Screen, or for Illuminating Halls or Buildings, on 
hire, either in town orcountry. Qualified Assistants 
sent if desired. Terms on application. 
JOHN BROWNING, 
OPTICAL AND PHYSICAL INSTRUMENT 
. MAKER 
To Her Majesty's Government, the Royai Society, 
the Royal Observatory, &c., &c., 
111, MINORIES, LONDON, E. 
Established 100 yeers. 
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