KNOWLEDGE. 



November, 1910. 



A REVOLUTION IN 

 HIGH SPEED SHUTTER WORK. 



multi-speed 

 paTnt shutter. 



ARRESTS 

 MOTION. 



Instantaneous f- 



Exposures 



without 



Sun light. 



NO HORIZONTAL % Q 



DISTORTION. 



EXTRA RAPID 

 INSTANTANEOUS 

 W EXPOSURES 



k Jic. 



\ ,.f SCLUIlJ. 



SLOWER 

 EXPOSURES 



With Ross' "HOMOCENTRIC" Lens the MULTI-SPEED 



f..ii,,, ill,. IV,! anil rnosi Kclml ik- Conil ,inal i. m U<\ .\ll ruipisr-. 



TELEPHOTOGRAPHY. Ross' HOMOCENTRICS 



arc particularly adapted for use a.s Pobilives. 



Ross' Tetenegattves are specially const>-itctcd /or use in conjunitiou 

 -,oith these remarkable Lenses. 



■.MODKKN TKLEPHOTOGKAPHY," a Practical Manual, hy Capiaii 

 OuhN WiihKLER. P;iper covers. 1/t) ; bevelled boaids, 2/(j. 



ROSS Ltd., 3, North Side, GLAPHAM COMMON, S.W. 



Every Modern 

 Engineering Book 



in the English language may be seen at 

 the Retail Department of 



E. & F. N. SPON, Ltd. 



57, HAYMARKET, LONDON, S.W. 



(iMlll.lhi..' Ml .\.,llis MH-CIL 



NO OLD EDITIONS STOCKED. 



// unable to come to London, write for Catalogue and 

 order the boolis through your local bookseller. 



BECK'S 



London Microscope 



(SMALL MODEL). 



W are supplying large numbers of this model for .students and 

 iHitanical work. The base and pillar are so designed that although 

 ilie Continental model is retained, the position of the inclining joint 

 is so placed a.s to give great stability in all positions. The stage is 

 3^" square and is faced with ebonite. The 

 coarse ailjustment is by solidly fitted rack 

 and pinion. The fine adjustment is by a 

 prismatic fitting worked with micrometer 

 screw. This tilting is absolutely solid metal 

 to metal, with no screws to shake loose, 

 and has proved by long experience to stand 

 tlie roughest use without damage. The 

 biid\- tube has a smoothly sliding graduated 

 draw tube. A double minor on a swinging 

 arm. and an iris diaphragm in 

 a sliding focu.ssing jacket are 

 supplied. It is finished in 

 lacc| tiered brass and is of best 

 workmanship throughout. Sup- 

 plied in a ver}' compact mahi_igan\' 

 case. 



Stand ^o. II2,5J, in case as 



ahovt £.t .T 



No. 364A, Kvepiece . . .i 

 No. S02, -;incli Ohject 



Glass II' 



No. S04, ; inch Ohjett 



Ulass I to 



No. :1<I2,\. Double Nose- 

 piece 9 



£6 1 



Full particulars of 



R. & J. BECK, Ltd., 



68, CORNHILL, LONDON, E.C. 



JAMES SWIFT & SON, 



^. Optical & Scientific Instrument Manufacturers. 



^^ |p 7 Gold Medals Awarded for Optical Excellence. 



IMPROVED PETROLOGIGAL 

 MICROSCOPE 



Y>. Kitted with (toss ^ Webl-t-d Ocular, 



7/a I'olaiiser and Auah.sui Coiiveiyent Svsteni 



adjustment tor 



\V1bK .V'y~7^ rolaiiserand .Aualv.sui Loiivi 



^M^j^^^^^ and ilcitrand Leii.s, with ai 



^^f^0^ if sliowini; Intel feieiice Fiynres. 

 j'^J2j^ ^' ^'^ Malioi;any Cabinet . 



£12 O O 



Ca/tj/oi;!/,: on df-/'.h.'<U/i.yi. 



University Optical Works. 



81, TOTTENHAM COURT ROAO. LONDON. 



BIOLOGICAL MATERIAL. 



Living and Preserved 

 Specimens for Class Work and Research. 



LIST FREE. 



L. HAIG, 9, Little James Street, Gray's Inn Road, London, W.C. 



OLD PLATINUM, GOLD 



Scrap, &c., valued or purchased. 



SPINK & SON, Ltd., 



17 & 18 PICCADILLY, W.. and at 

 6 KING STREET. ST. JAMES'. LONDON, S.W. 



ESTD. 1772. 



Oem.s lor experimental work at moderate prices. 



Typewriters 



MS5. Copied. 



I3()ught, Sold, I^epaired, 

 and Exchanged. 



Hire . . lOs. a Month 

 or 27/6 a Quarter. 



TAYLOR'S, LTD.,(°r ) 



74, CHANCERY LANE, LONDON, W.C. 



