A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE 



" To the solid ground 

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



No. 1870, Vol. 72] 



THURSDAY, AUGUST 31, 1965. 



[PpiCE' Sixpence 



Registered as a Newspaper at the General Post Offic 



NEW PATTERN "NEWTONIAN" 

 ELECTRIC LANTERN. 



CHEAP 



5067 New Iron Body Lantern, wuii hiass irni , i.ut 



mahogany board, 4-in. douLle Condenser, best full-size achro- 



inatic Front Lens, and " Newtonian " Hand-Feed Arc Lamp. 



Complete in Case £10 10s. 



3V 3ES A7V T O 3V «SC CO., 



OPTICIANS TO HIS MAJESTY THE KING 

 AND H R.H. THE PRINCE OF WALES AND THE GOVERNMENT, 



3 FLEET STREET, LONDON. 



PHOTOGRAPHIC LENSES. 



A SIMPLE TREATISE. 

 By CONRAD BECK and HERBERT ANDREWS. 



X -, Post Free 1/3. 



This somewhat difficult subject is made clear without 

 the use of mathematics. 



R. & J. BECK, Ltd., 68 CORHHILL, LONDON. 



PRACTICAL NOTES ON 



TELEPHOTOGRAPHY. 



Free on application to 



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



THE "IDEAL" LABORATORY 

 CLAMP. 



I>YE & CO., 



SCIENTIFIC INSTRUMENT MAKERS, 



GRANTA WORKS, CAMBRIDGE. 



LONG RANGE BAROMETERS 



THE DIAGONAL BAROMETER.— In ihU inslrument 



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



al column where in 6rdinary Mercurial Barometers the 



;.s would be marked, the tube is bent at an angle and 



aining 3 inches of the scare— viz. : 2p,'30, and 31 — 



nded over a tube 36 inches long, . . r. 



ying diagonally instead of - 



travels over 12 inches of the tube to every inq^h on the vei 



tical Jscale. , ' ( 



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

 divided, is at once noticeable and can be easily read withoi 

 the aid of a vernier or magnifier.. - 



/ Prices of this and other 

 amplication to tiie Manic/'aci7t 





NBGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT. 



45 CORNHILL, .AMI 122 REGENT STREET, 

 LONDON. 



