A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

 Of Nature trusts the, mind u'/iu/i builds for nyc."— Worlisworth. 



No. 1873, Vol. 72] THURSDAY, SEPTEMBER 21. 1905. ^ J I'kicr S ixpenci^ 



Registered MS a Newspaper at the G=ner.M Post Office.] _ [All Rights : 



:rved. 



NEWTON & CO.'S 



PATENT 



"DEMONSTRATOR'S" LANTERN, 



FOR LIMELIGHT OR ELECTRIC. 



With Prism for Erecting, 



and for Vertical Projection. 



Price £10 10s. 



3 FLEET ST., 

 LONDON. 



il 



The most simple 



and efTicient 

 Single Lantern 

 yet constructed 



for general 

 scientific work. 



THIS SEASON'S 



CATALOGUE OF 



SLIDES, &c., 



POST FREE. 



Apparatus 



for the 



determination 



of the relative 



conductivity 



of thin layers 



of materials. 



LEES' & CHORLTONS 

 METHOD. 



Catalogue of Part II., 

 SOUND, LIUHT & HEAI, 

 free on application. 



JOHN J. GRIFFIN & SONS, Ltd., 



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

 LONDON, W.C. 



r8,E'V3VOi:-i>s sz, :br.a.3m-sot>t, 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 

 to National Physical L.aboratory, Teddington, fitted for Gas, Water 



Ca/a/„;,u- »/ Chemlral 



nf A/'/'aratns, 350 //. and •> 

 on af'plication. 



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 



vertical column where in ordinary Mercurial Barometers the 



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



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



are extended over a tube ^j6 inches long. _ 



The mercury now moving diagonally instead of vertically, 

 ir.avels 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. 



Parllciilars and Prices of this and other loH^ 

 ^/■/•liLation to the ilannfacturcrs. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. 



P.RANCHES: 45 CORNHILL, AM) 122 REGENT STREET, 

 LONDON. 



