September, 1910. 



KNOWLEDGi:. 



AITCHISON & Co. 



Opticians to H.M. Go\ crnmcnt. 



The only makers in the world who have 

 succeeded in making 

 Prism Binoculars of 

 X 25 Magnification. 



PRICE £12 10 O 



with best solid te.itlier case. 

 ^\"ittl central focussing motion £1 extra. 



Every Glass Tested at the 

 BRITISH GOVERNMENT 

 LABORATORY AT KEW, 

 and Certificate of Power, Defi- 

 nition, &c., given with the 

 Glass to Purchaser. 



The Night and Day Marine, 

 £6 10 O 



Price v.\< iin.If p..i^ta::<- -Tiii pac'kir.-:; t < .i'..v y.n i ■ f I'l-j \\ nIJ. 



Illustrated Price List of Prism and other Binoculars post free. 



\\h\ buy foreign made glasses when the Aitchison is 

 British and best? 



AITCHISON &. Co. >^ 



Opticians to H.M. <S L.S.A. Oovts.. Ai^tft 



428, STRAND: 281. OXFORD STREET: 



6, POULTRY : and Branches. LONDON. 



LtiKus; 37, IJotiJ Street. 

 Ma.nchester: 3?, Market Street. 



TRADE MARK. 



H. K. LEWIS, 



publisher & bookseller, 



London, w.c. 



130, CiOW Kk STREtT, and 

 24, CiOWER PLACE, 



COMPLETEST STOCK OF TEXT BOOKS 

 AND RECENT SCIENTIFIC LITERATURE. 



ORDERS in PO-Sl PI^OMPIl.N ATTENDi;!) TO. 

 Agent for the Examination Papers oi the L niversitx- of London. 



SCIENTIFIC AND MEDICAL 

 CIRCULATING LIBRARY. 



ANNUAL SUlJsCKlI'lluN (T^uii ^, (,.„;;. .::;,) -.i^m ONE GUINEA. 

 gV~ Detailed Prospectus, vsith List of over 500 Recent Books, on application. 



n.v. 



■r 



■:-[ c, 



•i 

 I 



f^wS 



»• 



I 



SECOND-HAND 

 I APPARATUS I 



Bought, taken in Exchange for that of any g 

 other Maker, or Sold on Commission. 



,w- CataliiKue »( Seconil-Hand Apparatus read) middle Sepiemhcr. 

 H. F. ANGUS & CO., 



A REVOLUTION IN 

 HIGH SPEED SHUTTER WORK. 



MULTI-SPEED 

 SHUTTER. 



NEW 

 PATENT 



EXTRA RAPID 

 INSTANTANEOUS 

 EXPOSURES 



ARRESTS 

 MOTION. 



Instantaneous 



Exposures 



without 



Sun light. 



NO HORIZONTAL %j,,^ 

 DISTORTION. ^^^IS^^: 



With Ross' "HOMOCENTRIC" Lens the MULTI-SPEED 



forms the Best and most Reliable Combination for .VII Purposes. 



TELEPHOTOGRAPHY. Ross' HOMOCENTRICS 



i ic [),irticu].ulv a'iapted h>r use .i-- r'^iiive.-^. 



Ross' Tt^ I e negatives art: specially constrtutai /or use in conjunction 

 with these retnarkablc Lenses. 



MOBERX TELEPHOTOGRAPHY," a Practical Manual, by Captain 

 Owen Whefi.kr, Pnper cover*;, 1 'tt ; bevelled boarHs. 2/'**. 



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



^PROFESSOR GANONG S ^ 



Botanical Apparatus. 



! KAOE .\IAKK. 



\V 'ML MaKK. 



Photosynthometer 21 - Photometer 14-, 6 



Respirometer 28 - Manometer 4 2 



Leaf Clasp 27 - Leaf Area Cutter 50 - 



Demonstration Clinostat - 93 9 



Demonstration Auxograph 1 04/- 



Spectroscope 1 02 - 



Normal Light Screens 6 3 & 419 



DESCRIPTIVE LIST ON APPLICATION. 



Manufactuped by 



BAUSGH & LOMB OPTICAL Go. 



19, THAVIES INN, HOLBORN CIRCUS, 



^^^ LONDON. E.G. ^^k 



