A WEEKLY ILLUSTRATED JOIRNAL OF SCIENCE 



" To the solid ground 

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



No. 1872, Vol. 72] 



Registered 



THURSDAY, SEPTEMBER 14, 1905- 



Newspaper at the General Post Office.] 



[Price Sixpence 



(All Rights are Reserved. 



SYMPATHETIC PENDULUMS. 



One being set vibrating starts the other and itself is stopped, 



but resturting slops the other in turn. They continue for a 



long time starting and stopping each other alternately. 



THE NEV^^ 



"LONDON" 



MICROSCOPE. 



With Eye -piece | inch, | Inch 



0^ject • glasses, in Mahogany 



Case, 



£5 12s. 6d. 



Double Nose-piece, 9/- extra. 

 Focussing Substage, 14/6 extra. 



R. & J. BECK, Ltd., 

 68 CORNHILL, 



REYlNrOr-r»S *C BRA.3Sa-SOI«T, Ltd. 



Chemical and Scientific Instrument Makers to His Majesty's 



Government (Indian, Home, and Colonial). 



LABORATORY FURNISHERS and MANUFACTURING CHEMISTS. 



Ca/alogiie of Che. 



'riVSlCAI. KKNCH, illustrated above, as supplied 

 :al Laboratory, Teddington, fitted for Gas, Water 

 and Electricity. 

 al and Physical Apparatus, 350 //. and 



Illustrations, fn 



application. 



14 COMMERCIAL STREET, LEEDS. 



LONG RANGE BAROMETERS 



THE DIAGONAL BAROMETER.— In this instrument 

 he lube is much longer 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 

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

 nded over a tube 36 inches lone. 

 The mercury now moving diagonally instead of vertically, 

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

 tical scale. , ■ ,_ , , . 



The slightest variation, even 'ot" to winch the scale is 

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

 the aid of a vernier or magnifier. 



and Prices of this and other long 

 on af'plication to the Slannfactnrers. 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. 



Branches: 45 CORNHILL, and 122 REGENT STREET, 

 LONDON. 



