NA TURE 



[December 30, 1922 



Prof. Taylor Jones' 



ELECTROSTATIC 



OSCILLOGRAPH 



FOR POTENTIALS UP TO 

 250,000 VOLTS. 



Dr. Owen' s 



GOLD-LEAF 



ELECTROSCOPE 



As shown at the Physical 

 Society s last Exhibition. 



Full particulars on application to the Sole Makers : 



The Cox=Cavendish Electrical Si. 



TWYFORD ABBEY WORKS, 

 HARLESDEN, LONDON, N.W. 10. 



SECOND-HAND ZEISS MICROSCOPES 



ALL IN PERFECT CONDITION. 



I C Photo-micrographic Stand, revolving and centring stage, 



1 hi imati ondi riser, rack substage, 3 eyepieces, objectives A and 



I a . / ■ kton 'in her, objective changer with 4 slides, eyepiece 



d 1 tg mil 1 imi £30 O O 



IY A Stand, mechanical stage and spare revolving vulcanite stage, 



1 icking substage with swing-out Abbe and iri-. 2 evepieces, triple 



n sepiei • . A and I) objei tb 1 JE30 O O 



IY A Stand, spiral substage with Abbe condenser, a eyepieces, triple 



nosepiece objectives A and D (Zeiss) md ,', o.i. Watson 



£27 IO O 



1 A Stand, revolving mechanical stage and extra vulcanite stage, 



racking -ubstage. Abbe condenser, 2 eyepieces, AA and C ob- 

 jectives £27 IO O 



2 mm. Apo. Objective, 1.30 N.A.. t6o mm. tube length 



£15 O O 

 Abbe Camera Lucida £2 IO O 



Many others by all makers: list on application. 



CLARKSON'S, 338 High Holborn, London, W.C.I. 



W. OTTWAY & Co. Ltd. 



(Established 1640) 

 MANUFACTURERS ,, 

 of all types of Astronomical, 

 Surveying, Scientific and ' 

 Optical Instruments. 



Illustrated Leaflets post fiee. 

 We shall be pleased to give 

 quotations for Refractor Tele = 

 scopes up to 8 inches aperture, 

 fully equipped on Equatorial. 

 Silvering, Overhauling, Repairing & Adjusting do 



Orion Works, Ealing, London, 



OX YGEN 



And other Gases. 



The British Oxygen Co. have works for the production 

 of Oxygen, Nitrogen, Carbonic Acid, Nitrous Oxide, 

 Hydrogen, and Argon in all chief industrial centres. 

 The Company's Plants are capable of an aggregate out- 

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 Special Terms quoted to the Trade. 



Catalogue and full particulars on application to the Head 

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THE BRITISH OXYGEN CO., Ltd., 



ANGEL ROAD, UPPER EDMONTON, 

 LONDON, N.18. 



OLD PLATINUM, GOLD 



Dental Alloy, Scrap, &c. 

 Purchased for Cash or Valued. 



SPINK & SON, Ltd., 



Fine Jewels or Plate also purchased or valued. 



SCIENTIFIC APPLIANCES 



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SCIENTIFIC APPLIANCES, 11 & 29 Sicilian Avenue, London, W.C.I. 



A DICTIONARY OF APPLIED PHYSICS 



Edited by SIR RICHARD GLAZEBROOK, K.C.B., D.Sc, F.R.S. 



In 5 Vols. Medium Hvo. Fully Illustrated. £3 : 3s. net each. Orders for the complete set of five volumes will be 

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Vol. I. MECHANICS ENGINEERING— HEAT. [Ready. I Vol. IV. OPTICS, SOUND and RADI- 

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