A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

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



No. 1869, Vol. 72] 



THURSDAY, AUGUST 24, 1905. 



[Price Sixpence 



Newspaper at the General Post Office.] 



[All Rights 



Reserved. 



.JUST ISSUED. 



NEW ILLUSTRATED CATALOGUE 



(400 pages) of 



LANTERNS & SLIDES, 



Covering our Latest Improvements in Apparatus, and mapy 



Series of New Slides, including some of a Scientific and 



Educational Character. 



Sent post free anywhere for Sixpence. 



Also New Illustrated Catalogue of Sun-Dials, 

 32 pages, post free. 



NEIW^TON &; CO., 



Opticians to H.M. The King. H.R.H. The Prince of Wales, and 

 the Government, 



3 FLEET STREET, LONDON, E.C. 



RUBENS' LINEAR THERMOPILE. 



JOHN J. GRIFFIN & SONS, Ltd., 



Chemical and Scientific Instrument Makers to His Majesty's 



Government (Indian, Home, and Colonial). 



LABORATORY FURNISHERS and MANUFACTURING CHEMISTS. 



CHEMICAL AND PHYSICAL BENCH, illustrated above, as supplied 



tu National Physical Laboratory, Teddington, fitted for Gas, Water 



and Electricity. 



Catalogue of Chemical and Physical Apparatus, 350 //. and 1200 



Illustrations, free on application. 



Designs of Benches and Fittings to suit all requirements. 



14 COMMERCIAL STREET, LEEDS. 



NEGRETTI & ZAMBRAS 



LONG RANGE BAROMETERS 



THE DIAGONAL BAROMETER.— In this instrument 



the tube is much longer than usual, and at the point on ibie 



vertical column where in ordinary Mercurial Barometers the 



Id be marked, the tube is bent at an angle and 



ng 3 inches of the scale — viz.' : 29, 30, and 31 — • 



tended over a tube 36 inches lone. 



iw moving diagonally instead of vertically, 

 hes of the tube to every inch on the ver- 



tical scale. 



/The slightest 

 divid»'d, is at 

 the aid of 



" to vrhich the : 

 ble and can be easily read \ 



avd Prices of this avd other ion? 

 on afpliiation to die M,inuf.ictnrers. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. 



Branches: 45 CORXIIILL, and 122 REGENT STREET, 

 LONDON. 



