#^onian Inst/ty 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. \ 



To the solid ground 

 // Nature trusts the mind which builds for aye." — Wordsworth. ^^v^'Or-l 



No. 2277, Vol. 91] 



THURSDAY, JUNE 19, 1913 



[Price Sixpence 



[All Rights keserved. 



riSffiis^ 



BALANCES &WEIGHTS 



John J. Griffin & Sons, f 



KINGSWAY, LONDON, W.C. 



Scientific Instrument makers. 



/^y> w _ (f. V. Bovs-s Patent.) V* 



For Studying Liquid Films. 



Marvellous 

 Colour- 

 combinations 

 of Infinite 

 Variety. 



</ 



<6 



Unique 



Effects 



of 



Wonderful 



Beauty. 



Price 25/- Egfe ?£,£*$ 



Including 2 Bottles of special Soap Solution and Full Instructions. 



REYNOLDS & BRANSON, Ltd. 



Awards COLD MEDALS. ALLAHABAD. LONDON. 

 GRAND PRIX. TURIN. 



"RYSTOS" OPTICAL BENCH 



Optical Bench for lantern, one metre long, wiihout fittings, £1 10 0. 



Sliding tables, 3/6 each. Lens holders, 4/6. Adjustable slit, 4/9. 



Screen holder, 4/- Standard candle holder, 1/- Circular table, 1/6. 



Screen with gauze, 3/6. Rotating holders for nicol prisms graduated at 



o 1 , go", 180" and 270 , 9/- Glass prism 60 , mounted in special holder, 4/6. 



Half-metre extension with foot, 12/6. 



The above can also be used without the lantern as an ordinary optical 



bench, and any part can be supplied separately. 



New Descriptive Circular of Accessory Apparatus for the 



"S. & R" lantern, post free. 



14 COMMERCIAL. STREET, LEEDS. 



Negretti & Zambra's Traveller's 

 Companion — Aneroid, Compass, 

 and Thermometer, in case — is a 

 useful and acceptable present. 



Price list of 

 " Barometers " 

 sent free on 

 request. 



NEGRETTI & Z AM BRA 



Scientific Instrument Makers, 

 Holborn Viaduct, London, E.C. 

 City Branch : 45 Cornhill, E.C. 

 West End: 122 Regent St., W. 



