A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

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



No. 1 87 1, Vol. 72 J 



THURSDAY, SEPTEMBER 7, 1905. 



[Price Sixpence 



Newspaper at the General Post Office.] 



[All Rights 



Reserved. 



Newton's New Demonstrator's 

 "Transpaque" Lantern 



Has all the advantage 

 of our well-known 

 " Demonstrator s 

 Lanterns, and m 

 addition will show 

 brilliantly on the 

 screen, opaque 

 objects or book 

 illustrations, if not 

 larger than i 

 large postcard 



ih.. 



NEWTON & CO., 3 FLEET STREET, LONDON. 



Apparatus 



for the 



determination 



of the relative 



conductivity 



of thin layers 



of materials. 



LEES' & CHORLTONS 

 METHOD. 



Catalogue of Part II., 



SOUND. LIGHT & HEAT, 



free on application. 



lllilMMIIIilTllll ^ 



JOHN J. GRIFFIN & SONS, Ltd., 



20-26 SARDINIA ST., LINCOLN'S INN FIELDS, 

 LONDON, W.C. 



XKE^srnaroiL.DS «c ^xz.-A.srsoiM', 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 su] 

 to National Physical Laboratory, Teddington, lilted for Gas, Wa 

 and Electricity. 

 Calalogitd of Cheinkal and Physical A/>/>aratiis, 350 //. and : 

 Illustrations, free on application. 

 Dfsigns of Benches and Fittings to suit all reouireme 

 14 COMMERCIAL STREET, LEEDS. 



LONG RANGE BAROMETERS 



THE DIAGONAL BAROMETER.— In this Instrument 

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

 \ertical column where in ordinary Mercurial Barometers the 

 ::'■'.• 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 long. 



The mercury now moving diagonalh" instead of vertically, 

 travels over 12 inches of the tube to every inch on the ver- 

 tical scale. 



The slightest variation, even '01" to which the scale is 

 divided, is at once noticeable and can be easily read without, 

 the aid of a vernier or magnifier. 



Further Particulars and Prices of this and other long^ 

 rau^e Barnnicters sent on application to the Manufacturers^ 



NEGRETTI & ZAMBRA,' 

 38 HOLBORN VIADUCT. 



: 45 CORNIIILL, and 122 REGENT STREET 

 LONDON. 



