October, 1910. 



KNOWLEDGE. 



AITCHISON & Co. 



Opticians to fi.M. Government. 

 The only makers in the world who have 

 succeeded in making 

 Prism Binoculars magni- 

 fying 25 diameters. 



PRICE £12 10 O 



w ith best solid leather case. 

 Wit!) ocntr.ll fociissiiiL; motion £"1 e.\tr.T. 



Every Glass Tested at the 

 BRITISH GOVERNMENT 

 LABORATORY AT KEW, 

 and Certificate of Power, Defi- 

 nition, &c., signed by Dr. 

 R. T. Glazebrook, F.R.S., 

 the director, is given with the 

 Glass to Purchaser. 



The Night and Day Marine Wide Aperture Prism Glasses. 



X 9 MAGNIFICATION £6 10 x 16 MAGNIFICATION £8 10 



X 12 MAGNIFICATION £7 10 x 20 MAGNIFICATION £10 10 



X 25 MAGNIFICATION £12 10 



Prices include I'esl .Solid Leather Sling Case, postage and packing to aii\' 

 part of the World. 



Price List o/ Prism and ot/iir Binocttiars Post Free. 



AITCMISON & Co. 



Opticians to H.M. A L.H.A. (io\ts.. 



428, STRAND, and Branches, LONDON. J 



■IKa 



Lefds : 37, Bond .Street. Manchester: ■:;:;, Maikct Sir 



IRADE MARK. 



\I-:W BOOKLET ( 



THOTOMICROGRAPHY' ( 



ColUailiing a (ll^c^lNsI,.ll (.1 Uic cnnsi(icr;uiMiis o.,\^.],i. ^ 



ini; the Contrast obtained In the Photography (• 



of Microscopic Specimens. C 



Free on application, ciiclosi)!-^ Id. stamp L 



for postage, to f 



WRATTEN & WAINWRIGHT, Ltd., CROYDON. ( 



•« 



I 



SECOND-HAND 

 i DEPARTMENT j 



Apparatus Bought, taken in Exchange for that 

 of any other Maker, or Sold on Commission. 



.*~ Calaln^ue ol' Setnnd-Hanil Apparatus .NOW RHADV. post irc-c. 



H. F. ANGUS & CO., 



83, VVIQMORE i^T., CAVENDISH SQLARH, LONDON, V\ . 



FLewis's Circulating 



I Medical and 



Scientific Library. 



( ,v>-iui- tilt Mil.jc. 1^ f Astronomy, Bioloji:\ . Botany, Cliemislry, 



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Zoology, &c., in a'ltiiti'>n tu Every Branch of .'Mr v,il >>.iiiKc. 



.Vfu- U'orAs and Sew Bd'itions are added to the Library 



immediately on publication. 



Subscription, Town or Country, from 21s. 



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,iiv r-T ihf 



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1^ London 



London : H. K. LEWIS, 136, Gower Street, W.C 



BOOKS IN ALL DEPARTIYIENTS OF LITERATURE 



BAUSCH & LOMB'S 



CELEBRATED 

 MICROSCOPES. 



Nev\^ and Improved Models- 



B H 8 LABORATORY MODEL (as figured) 

 with J-in., ,'.-ii'-- •""' ,^-iii. (oil imiiieisioii) objectives, 

 2 eye-pieces, screw-out subslage, \\ itli Abbe con- 

 denser, and triple dust-proof nosepiece. in cabinet, 



£13 2 6 



B B H .s LARGER LA BORA- 

 TORY MODEL, ..- ^,l,;v^. l.ut 

 with scrc«'-oiu ii/!tr sw iiiL:-(liiu ii 

 sul.Mage £18 4 6 



and 



and 



B H 4 MODEL, with ?, 

 '•in. objectives, 2 eyepiect; 



ircnlar tiiist-pruof no.sL-pitct-, 



£5 12 6 



Microtomes, Centrifuges, 

 Photo - micrographic and 

 Projection Apparatus, 

 Precision Laboratory 

 Glassware, &c. 



. k 



ispeclion cordially invited at our 



THE BAUSCH & LOMB OPTICAL Co., 



i.'.')!:r,[i (iws to British and Foreign Govcfnti/fnt.^. 



19, THAVIES INN, HOLBORN CIRCUS, 

 LONDON, E.C. 



A 



