A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



** To the solid ground 

 Of Nature trusts theniiiid which builds for aye." — Wordsworth.; 



No. 1874, Vol. 72] THURSDAY, SEPTEMBER 28, 1905 | Price Sixpence 



Registered 



Newspaper at the General Post Office.] 



[All Rights ; 



NEWTON & CO., Opticians to the Kin^ 

 3 Fr-EET sxke;et, x^oi«x>on. 



PHOTOGRAPHIC LENSES. 



A SIMPLE TREATISE. 



By CONRAD BECK and HERBERT ANDREWS. 



A/-, Post Free 1/3. 



ThiK somewhat difficult subject is made clear without 

 the use of mathematics. 



R. & J. BECK, Ltd., 68 CORNHILL, 



PRACTICAL NOTES ON 



TELEPHOTOGRAPHY. 



Free on application to 



R. & J. BECK, Ltd., 68 CORNHILL, 



OUR ILLUSTRATED CATALOGUE 



PHYSICAL APPARATUS 



IS 3VO-W ItEA-D^ST. 



See Notes, "Nature," p. 518, Sept. 21, 1905. 



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NEGRETTI & ZAMBRA'S 



LONG RANGE BAROMETERS 



THE DIAGONAL BAROMETER In this instrument 



the tube is much longfr than usual, and at the point on the 

 vertical column where in ordinary Mercurial Barometers the 

 28 inches would be marked, the tube is bent at an angle and 

 the remaining 3 inches of the scale — viz. : 29, 30, and 31 — 

 are extended over a tube 36 inches 'one. 



The mercury now moving diagonally instead of vertically. 



cal 



inches of the tube 



ery 1 



the 



The slightest 

 divided, is at on 

 the aid of 



' to which the scale is 

 1 be easily read without 



'■•urther Parlicnlars ami Prices of this and oilier loK^ 

 iXn^cBarimclcrs sent oil affliiatian to the Maiiiifacturcrs. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. 



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 LONDON. 



