Siifplemcnt to ''Nature'' December 29, 192 1 



111 



X-RAY 



APPARATUS 



The Directors of the COX-CAVENDISH 

 ELECTRICAL Co., Ltd., have pleasure in 

 announcing the publication of a new and unique 



CATALOGUE OF X-RAY 

 APPARATUS & ACCESSORIES 



This publication consists of 170 pages, fully 

 describing and illustrating every modem type 

 of apparatus, and includes many new designs 

 of the Company's specialities. 



This remarkable publication, which is un- 

 doubtedly the most comprehensive yet pro- 

 duced in this industry,', will be forwarded on 

 application, POST FREE. 



GREAT REDUCTIONS IN 

 PRICES HAVE BEEN EFFECTED 



The Cox-Cavendish Electrical Co., Ltd. 



TWYFORD ABBEY WORKS, 

 HARLESDEN, LONDON, N.W.IO 



IONIUM 



Permanent Alpha Ray Activity 



RADIO-LEAD 

 MESO-THORIUM 



Gl«w's Scintilloscopes charged with IONIUM, 

 RADIUM, MESO-THORIUM, or ACTINIUM, 



T/6 each. 



Scintilloscopes showing Double Scintillations 



Thorium "A," 15/- each. 



F. HARRISON GLEW, 



1S6 CLAPHAM ROAD. LONDON. S.W. 9 



SCIENTIFIC GLASSWARE 



Graduated aud Lamp-blown. 



HOWARD, RAWSON & Co., Ltd. 



Manufacturers of all kinds of 



GLASS INSTRUMENTS 



for Chemical and Medical use. 



LAMPBLOVVN GLASSWARE in Wholesale Quantities. 



21b POND PLACE, CHELSEA, S.W. 3 



Telephone: KENSINGTON 3736. 



BRITISH 

 GLASSWARE 



Manufactured by BRITISH Labour under 

 the supervision of BRITISH Chemists. 



RESISTANCE 

 GLASS HOLLOW. WARE, 

 ACCURATE GRADUATED 

 WARE. LAMP BLOWN 

 WARE, TUBING AND 

 ROD OF SODA OR 

 RESISTANCE GLASS. 



TO. 



DUROGLASS, L 



Conlraclors to the L.C.C, RyiJ^., War Office. Croicn Agents 

 to the Colonies, Indian Coct., The Royal Arsenal, etc. 



SHOW ROOMS AND SALES DEPT., 



40-43 Norfolk Street, 

 Strand, London, W.C. 



Tel., CENTRAL 931-2. 



-/ 



DOLLOND 



1 6-in. Oollond Objective N.A. 0-74 . . £2 is 



2 3-in. „ „ N.A. 0-22 .1 5 

 1 12-in. Zeiss Apoch. oil im. N.A. 1-3 ..IS 

 1 12-ln. Bauseh & Lomb oil im. N.A. 1*3. . 7 

 1-in., i-in., i-in. Dividing Objective 12 

 Watson Microscop«, lo-in. tube, mech. stage, with 



hor. and vert, motion, rotating stops, i eyepiece, z 

 objectives, I -in., J-in., case. Reduced to . . f7 15 



Spencer Microscope, fine adjust., mech. stage, triple nosepiece, rack 

 swing-out substage, iris and stop carrier, .\bbe, condenser, 3 objec- 

 tives, 2'3-in., I 6in. and i-i2-in. oil, 2 evepieces, cabinet £23 • 



Leitz Entomological Microscope No. '2, objective No. 3, 2 eye- 

 pieces, cabinet ... . . M IS 



4^x3^ Contessa Duroll Roll Film Camera, double extension, 

 Zeiss Tessarf4'5 lens, Compur shutter i sec. to 1,250th rise and 

 cross, level, new .. .. .. .. . . t17 10 



Se-u- Bargain List Free. Easy pavmcnts arranged. 



2 NORTHUMBERLAND AV., W.C. 2. Est. 1750. 



MICROSCOPE 

 REPAIRS & ADJUSTMENTS 



We undertake the cleaning, repair and adjust- 

 ment of any make of Microscope, or other 

 instrument, and, if desired, shall be glad to 

 send an expert to carry out such work for 

 Colleges, Institutions, etc., without removing the 

 apparatus, where such a course is practicable. 



MALES and ANDREWS, 



Makers of all kinds of Scientific Apparatus, 



18a Iliffe Yard. Walworth Road, 



London, S.E. 17. 



