March, 1907.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



SALE. 



Season's Stock. 

 Unique Opportunity 



8,000 LANTERN SLIDES. 



Plain - 6d. each. 

 Coloured 1/- each. 



BEST PHOTOGRAPHIC SLIDES, 



COMPRISING ALL SUBJECTS. 



Chromatropes. Dissolving Sets. 

 Mechanical Slides. 



AT ONE-THIRD ORIGINAL PRICE. 



OPTICAL LANTERNS. 



Russian Iron & Mahogany Bodies. 



SIX DOZEN LANTERN OBJECTIVES 



(VARIOUS FOCI). 



JETS, CONDENSERS, SLIDE CARRIERS, 



OIL LAMPS, LIMES, 

 GAS CYLINDERS, FITTINGS OF ALL KINDS, 



At one-third less than usual price. 



Special Sale Price List Gratis ami Pest Fret on 

 request to: — 



W. WATSON & SONS, 



313, HIGH HOLBORN, 



LONDON, W.C. 



1^1^) 16, FORREST RD., EDINBURGH. 

 2, EASY ROW, BIRMINGHAM. 



ESTABLISHED 1837. 



•HORNTON-PlCRARD 



ia .. -®)- 



.^Sl 



"IMPERIAL TRIPLE EXTENSION." 

 7Q - OUTFIT 



(Half Plate Size). 



Tbe "Outfit" is supplied complete 



and includes: Camera with Turntable, 



Blide, Thornton-Pickard Time and 



Instantantous fchutter with Speed 



ndicator, Beck Symmetrical Lens with Iris 



Diaphragm, and three-fold 'Iripod. 



THE THORNTON-PICKARD MANUFACTURING CO., LT0-, ALTRINCHAM. 



DENT'S CLOCKS, 



WATCHES, AND CHRONOMETERS. 



FOR SCIENTIFIC USE. 



Sidereal or Mean Time Clocks for 

 Observatories, £21 and upwards. 



E. DENT & CO., Ltd., 



WATCH, CLOCK & CHRONOMETER MAKERS 



By Special Appointment to H.M. the Kin-. 

 Makers of the Great West- 

 minster Clock, Big Ben. 

 Makers of the Standard 

 Clock of the Royal Ob- 

 servatory, Greenwich, and 

 the Principal Observatories 

 throughout the world. 



„ — - TRADE MARK 



Only Addreuet— 



61, STRAND, and 4, ROYAL EXCHANGE, LONDON. 



BEST 

 COCOAI 



SCHWEITZERS 



EARTH 

 GUARANTE 



KING, SELL&OLDING, Ltd., 



-a* PRINTERS & PUBLISHERS .|=~- 

 27, Chancery Lane, LONDON, W.C. 



Special facilities for the printing and 

 publishing of Scientific Books, etc. . . 



Also for Che printing of Scientific and Optical Instrument Catalogues. 



Midnight Skv from the Golden Gallerj of St. Paul's on"> apotogiu 



to the ituimtBvimct of Mtnrnmt/h 



A. BOURNE & CO., The London Engravers. 



Copper. Half Tone. Line Zinco, Woodcuts. 

 SCIENTIFIC AM) NATURAL HISTORY SUBJECTS A SPECIALITY. 



Vofcen of r'tr Block* ttftil in thi) Journal, 

 73 ludg^vte HILL, E.C Telephone: 3(03 Central. 



