VI. 



KNOWLEDGE & SCIENTIFIC NEWS. 



[January, 1907. 



ZEISS 



PALMOS CAMERAS 



Made of light metal, 



strongly and accurately built. 



Fitted with ZEISS lenses. 



Take Plates, Flat Cut Films, Roll Films 



and the new Zeiss Pack - Slide. 



Sizes — 6xo.ind ox I2cm.,and 3JX4J in.,and 5 in x 4 in 

 Also ox 1 2 and gx iS cm. for Stereo and Panorama. 



Itluslraled Catalogue, "P.K." Post Fire on application. 



CAnL ZEISS) 29. Margaret St., Regent St., London, W. 



|ryj| Berlin — Trankfort o/M. — Hamburg — \'iemi.i 



'JCnHi -St. Petersburg. 



MACMILLAN'S NEW BOOKS. 



AT THE BACK OF THE BLACK 

 MAN'S MIND. 



Or. Notes on the KinKly Office in West Africa. By R. F.. 

 l>I-:NNr.TT. With Ilhistrations, Kvo, los. net. 



THE LOWER NIGER AND ITS TRIBES. 



I'.v Major AKTIIt'K GI.YX I.r.ONARD With a M.ip, 

 «vo, I2S. fid. net. 



THIRD EDITION NOW READY. 



SCIENTIFIC LECTURES. 



Hy I. OKI) AVIBl'K'l', .^vo, '.s. net. 



THE MANUFACTURE OF LIGHT. 



A I ciuirt- .lili\crcil .-u iho Meeting of the British .Association 

 at York. By SILVANUS P. THOMPSON, D.Sc, F.R.S. 

 Crown 8vo, is. net. 



TRIGONOMETRY FOR BEGINNERS. 



By Rev. J. B. LOCK, M.A., and J. M. CHILD, H.A., 

 Globe 8vo, 2s. 6d. 



FIFTH EDITION NOW READY. 



NUMERICAL TABLES AND CONSTANTS 

 IN ELEMENTARY SCIENCE. 



By SYDNEY LUPTON, M.A,, F.C.S. Fcap 8vo, 2S. Cd. 



THE LIFE OF ANIMALS. 

 THE MAMMALS. 



By ERNEST INGERSOLL. With Coloured Plates and 

 otlier Illustrations. Extra Crown 8vc, 8s. 6d. net. 



MACMILLAN & CO., LTD., LONDON. 



FOUR EXPERT OPINIONS 



ON 



BAUSCH & LOME'S 



MICRO-OBJECTIVES. 



Mr. F. SHILLINGTOX SCALES, B. A., F.R.M.S. (Microscopical Editor of 



Knoich'ilQe and Scittitific News), says in the July issue of that Journal ; — 



NEW OIL IMMERSION OBJECTIVE. 



Messrs. A. E. Staley & Co. have sent me, for examination, a new 



i-i6th inch homogeneous Immersion Objective, with a numerical aperture 



of r3, made by the Bausch & Lomb Optical Co. ... Of the Jens 



under notice I can speak highly. Its definition is excellent. And its 



working distance ample. I have tested it on some difficult spirilla, as 



well as in more theoretical ways, and was much pleased with its 



performance. 



Dr. B. writes: "I have taken some pains to test the Bausch & Lomb 

 i-i2th Oil Immersion Objective you sent me, against an English Objective 

 of same power, but corrected for long tube — the Bausch & Lomb is 

 undoubtedly the better lens — it is a very fine specimen indeed, therefore I 

 am keeping it, and enclose bank draft." 



Dr. D. writes: "The colour corrections and resolving power of your 

 high-power Objectives are perfect, and compare very favourably with the 

 high-priced objectives made in Europe." 



Dr. S. writes : "Speaking of your High-Power Objectives ii2ih Oil 

 Immersion. It is extremely perfect in every detail of my tests, and they 

 are very severe. I assure you. If you are yourself a microscopist, you will 

 appreciate that I tell you I counted the dots in ' Amphipleura Pellucida ' 

 i/ioo,oooth of an inch, quite easily even with green light, almost the actual 

 theoretical limit of visibility. It is one of the finest Objectives I have 

 ever tested." 



2'3rds Dry, i;'5th Dry, i i:th Oil Imm. i/iGth Oil In 



PRICES: 15/- 30/- 100/ 



160/ 



Corrected for 160 mm Tube Length. 



Write for lUuslrateti Mirro^^copieul Catnloriue (SJ pp.), 3 Stanifn to cnvfr 

 postage^ to the Sole B'^prenentatives 0/ the BAUSCH & LOMB OPTICAL 

 CO., for U.K. nii4 Colonipn. 



A. E. STALEY & CO., 



Contractors to the British, Indian, and Colonial Governments, 

 Principal Hospitals, Colleges, and Schools of Bacteriology, 



19. THAVIES INN, HOLBORN CIRCUS. LONDON, E.G. 



STUDIES IN 

 MICROPETROGRAPHY. 



Imperial Siv, uitli FiiU-Piige Philes in Niitiii<il C'loiin, Key 

 Vi.itt's, Exphvijtoiy Text and 4S Miii'isci'pical Pnparations. 



BEAUTIFULLY COLOURED PLATES. 



Twelve Monthly Parts, post frea to Subscribers 

 only, £4 4 O net. 



Subscribers who desire to pav their subscriptions by instal- 

 ments, MONTHLY orQUARTEKLY, may do so by paying 

 Seven Shillings monthly or One Guinea quarterly in advance. 



SUBSCRIBER'S ORDER FORM WILL BE SENT ON REQUEST, POST FREE. 



SPECIAL NOTICE. 



IT HAS BEEN SUQQESTED that many students 

 would like to possess MEGASCOPIC SPECIMENS 

 of the Rocks, &c., for their collections, so as to 

 familiarise themselves with the naked»eye appear- 

 ances of the objects. Such has therefore been 

 arranged, and 



THE SERIES OF 48 SPECIMENS will be 

 available to subscribers only, at £1 Is. Od. net, 

 in advance. Single specimens may be purchased 

 by subscribers or non = subscribers at 9d. each, 

 post free, from : — 



ROBERT SUTTON, 



PUBLISHER, 

 43, The Exchange, Southwark, London, S.E. 



