KNOWLEDGE., 



November, 1910. 



IMPROVED 



HORIZONTAL & VERTICAL CAMERA 



PHOTO-MICROGRAPHY 

 Photography of Larger Objects. 



Ft Plates 21X21 r/m or 

 smaller. 



Kxteiision of bellows about 

 I metre. 



PRICE, complete with one ^^Ck 

 Double Dark Slide, ^^^y. 



Optical Bench. £1. New Inverted) Burner, on Stand, £1. 



Collective Lens System, with Iris Diaphragm, on Stand. 



£1 16 O. 



Prospectus, ** Micro. 238," post free. 



CARL ZEISS (London), Ltd., 



13-14, Great Castle St., Oxford Circus, London, W. 



^T NEW ^^ 



'laboratory MICROSCOPES^ 



FOR STUDENTS' USE 



MODEL <;. ns illustrated, medium size stand h.iving improved horse-shoe 

 base, curved Hmb idcliiiabie to an angle of 45', large stage measuiiiig 

 4"X4". rack .irid pinion coarse adjustment, new safety fine adjustment 

 having endless motion in either direction — absolutely pievents breakage 

 of cover glasses or injury to front lenses of objectives, 

 and guaranteed more durable than fine adjustments 

 involving the use of micrometer screws; one complete 

 revolution of milled head actuates tube o'l mm. 

 (i^fi inch). Price, with cylinder diaphragm, having 

 set of three stops — 



Achromatic objectives 3" and I", £ s. d. 

 eye pitce II, double nosepiece 7 S O 

 Abbe condenser, iris diaphragm and 



vvorm focussing screw . . - . "1 1 O O 



Oil immersion object 



<^" 



I'o", eye piece IV, 

 and triple instead ol 

 double nosepiece 



510 



E. LEITZ, Oxford House, 9, Oxford St.. London, 



.!:;,!//\ III all Uuiversitv CeiUris. 



£14 5 O 



.MODEL G L, same 



as G, but having lever 



fine adjustment, 



achromatic objectives 



3" and i", eye piece 



n, and simplified 



double nose piece 5 1 5 O 



Abbe condenser, irisdia- 



-phiagm_ and worm 



focussing screw 1 10 O 

 Oil immersion ob- 

 jective •^:," . eye 

 piece IV, and 

 triple instead 

 of double nose- 

 piece ..515 O 



£13 O O 



on,W. i 



Messrs. BELL S BOOKS 



PRACTICAL ELECTRICITY 

 AND MAGNETISM. 



A P'irst \ ear's ("ourse. 

 By R. ELLIOT STEEL, M. A., Senior Science Master, Sherborne School. 



EXERCIS.es IN METAL WORK. 



Vox Traiic Preparatory .Schools. 

 By A. J. KERSEY, A.R.C.Sc. 



INTRODUCTION TO 

 INORGANIC CHEMISTRY 



By ALEXANDER SMITH, 



II. Si:. (Kilin.), Ph. I). (Muiiidi). F.K.S.E., ProfesMir ol Chemistry .iiid Diiwlor 

 of (General aiitl Physical Chemistry ill the Univeisity, Chicago. 



Now in use at the following Universities :— 



Kiliiilmrsh, P.iriniii;;ham. ShelTleld. Li\i:r| I. St. .Viuircus, Diiiicice. 



UiiivCTsity College (l.ondoTil, I.ee.ls. Prist..!. Pomlay, .Madras. Hoh.irl. 



Melljoiirne. and in schools and colleges all over the world. 



* .* Ccrinaii and Portic^itcsc Translations of this zi'ork arc ntn^' pul'li!.hcii. 



P.Y THE SAME AUTHOR. 



j^th I li,<iisan,i. n,. K.I. „, : 



GENERAL CHEMISTRY FOR 

 SCHOOLS & COLLEGES 



"All uiiuh.ivc used tlic ,iLilhui'> ■ Ihtroducti^ii Uj Gci.^-i.tl li.Mr^.uii. 

 Chemistry ' will give a hearty welcome to this more elementary text-book. . . . 

 There is no text-book of systematic and theoretical Chemistry which we would 

 sooner place in the hands nf a boy in his sixth form at school or his first year at 

 the University." — School M'oi-ld. 



2isi Thousand. Crown St'p. 



. ^d 



A LABORATORY OUTLINE 

 OF GENERAL CHEMISTRY 



Revised in collaboration with WILLIAM |. HALE, Instructor in C.enei; 



Chemistry in the Lrnisersity of !VlichiL;an. 



146 pages, interlea\'ed tiirMnghoiiI. With ji , Ilhistralii ms. 



London: G. BELL & SONS, Portugal Street, W.C. 



ASTRO-PHYSICS. 



EXAMINATION OF SUN SPOT 

 SPECTRA. 



The mo5t suitable instrument for this work 



is the Littrow Type Spectrograph 



(see rriil. Hale's Lecture puiiled iii the Mi 

 Roj'al AstronomictU Sncieiv. Vol. LW'III. 



iitlilv X.itn-t 

 , No'. I, Xiiv 



i)f the 

 1907). 



PHOTOGRAPHY OF STELLAR 

 SPECTRA. 



Objective Prisms of any size for the photo- 

 .tfraphy of stellar spectra can be supplied, often 

 at short notice. ()\\ iny; to the number of lartre 

 hijfh' class prisms made by us, we are able to 

 stock large blocks of the best optical sflass for 

 all kinds of prism work. 



LIST OF ASTRONOMICAL SPECTROSCOPES POST FREE. 



ADAM: MILGER, Ltd., 



75a, CAMDEN ROAD, LONDON, N.W. 



Awarded ORAM) PRIZE, Brussels Exhibition, ipto. 



Illustrated Lists of Spectroscopes aad Spec- 

 troscopic Apparatus of all kinds post free. 



'telegrams ; "Sj-hkricitv. Lumion-.' 



Tel,.,,l,o: 



XuKrii 16S7. 



