A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

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



%onal MoSSS^ 



John J. Griffin & Sons, L T 



KEMBLE ST., KINGSWAY, 

 LONDON, W.C. 



Scientific Instrument makers. 



The GRAY-BURNSIDE 



MOTOR - GYROSTAT 



With 10 attachments for demonstrating all the pro- 

 perties and practical applications of the Gyrostat. 



Descriptive Booklet, with Prices, on Application. 



Gyrostatic Pendulum. 



GRAY'S GYROSTATIC MODELS 



Prices on Application. 



REYNOLDS &. BRANSON, Ltd. 



CRAND PRIX AWARD. TURIN, 1911. 



SOLE AUTHORISED MAKERS OF 



STROUD & RENDELL SCIENCE LANTERNS. 



• The " University " Lan- 

 tern, with Russian iron 

 body, sliding baseboard, two 

 superior objectives, plane 

 silvered mirror " A," which 

 is moved by a knob causing 

 the rays to be reflected 

 upwards for the projection 

 of objects in a horizontal 

 plane, condensers 4 J in.,diam., 

 prism with silvered back 

 which can be used at "C," 

 or as an erecting prism 

 ■' D," lime-light 



slide 



Prii 



Re 



■r-il.le 



, with " Phcenix " Arc Lamp 



adjustable platform "B" for supporting apparatus, 



plete in travelling 



without reversible adjustable 



platform " B," £10 7 6 



11 15 



The " College " Lantern, without adjustable platforn 



lime-light burner complete .. 



Ditto, ditto, with " Phcenix" arc lamp 



Slit and prism ftr spectrum with support, for either Ian 



Polariser and analyser 



Catalogues post free. 

 Optical Lanterns and Accessory Apparatus, 223 pages. 



icals, 44 pages. 



Con 



14 COMMERCIAL STREET, LEEDS. 



Negretti & Zambra have 

 been constructing and 

 improving Deep-Sea Ther- 

 mometers since the year 

 1857. Patentees in 1874 of 

 the original Reversing Deep- 

 Sea Thermometer, the latest 

 model — illustrated — being 

 up-to-date in all respects. 



Particulars and prices 

 sent free on request. 



NEGRETTI & ZAMBRA 



Scientific Instrument Makers, 



Holborn Viaduct, London, E.C. 

 City Branch : 45 Cornhill, E.C. 

 West End : 122 Regent St., W. 



