LUME XXXIII. NUMBER 507. 

 ew Series. Volume VII. Part lo. 



Articles : 



OCTOBER, 1910. 



FOLNDED BV RiCHARD .\. ProCTOR, 1S61. 



-Plainly Worded. Subjects :— Exactly Described. 



OXE SHILLING NET. 

 Entered at Stationers' Hall. 



SECOND-HAND 



DEPARTMENT. 



OCTOBER Issue of Second-Hand List, 



containing particulars of over 1 ,700 



items, now ready. 



POST FREE OiV APPLICATIOS. 



C. BAKER 



244, High Holbopn, London. 



i'Establlshed\ 

 I 1765. ,' 



MAKERS of NEW TELESCOPKS. OBJECT 

 CLASSES, EVE-LEXSES, PRISMS, .iiid other 

 AS I Rd XOMlCAL APPARATUS, Elc. 



BROADHURST, CLARKSON & Go. 



63. Farpingdon Road, London, E.C> 



( ?'? years at ^S. fiarlU-^t's Builitings.) 



DEALERS in SECOND-HAND TELES- 

 COPES, .MICROSCOPES, LANTERNS, ami 

 ACCESSORIES AKo PRIS.M and ORDINARY 

 FIELD GLASSES. Etc, Etc. A Larje and varied 

 Stock l>v the Best Makers always on offer. 



No other Beverage 



(fives so much Strength and Vitality 

 to the System as Cocoa when manu- 

 factured with the care and on the 

 principles embodied in 



PURE CONCENTRATED 



" HAS WON MORE AWARDS THAN ANY OTHERS ." 

 HEALTH IN EVERY CUP. 



Makers to H.M. The King, H.M. 



The Queen, and H.R.H. The 



Prince of Wales. 



And to the People for nearly 200 years. 



POCKET 

 FIELD MICROSCOPE. 



Pocket Field Micro- 

 scope, with Forceps 

 to hold object, double 

 lens, in lined case. 



Post 



15/6 



NEWTON & Go., 



Opticians to 



His Malesty the King, 



3, Fleet Street, 



LONDON. 



CHCMICAL, PHYSICAL, and I 



SCIENTIFIC APPARATUS, 



CHEMICAI.S, REAGENTS, 



Etc., Etc. Ri I 



Awarded Grand Prix Franco-British Exhbn., 1908; 



Nine Medals at the Pans Exhibition, 1900; 



London, 1862; Paris, 1867; London, 1885; 



Philadelphia, 1876. 



JAS. J. HICKS, 



8, 9 & 10, Hatton Garden, London, 



Scientific Instrument Maker 



To H.M. Home, Indian, and Colonial Govern- 

 ments, many Foreign Governments, and the 

 Principal Observatories, Universities and 

 Colleges throughout the World. 



MANUFACTURER 



OF 



STANDARD METEOROLOGICAL 

 AND SCIENTIFIC INSTRUMENTS 



OK EVKBV DESCRII-TIi'N, INCLUDING 



CLINICAL THERMOMETERS. 



Catalogues, Estimates. S- all Information free by Return. 



ANY KIND OF SCIENTIFIC INSTRUMENT 

 M A PE TO ORPE R. 



Exceptional Tenns to Colleges, Institutions^ etc. 

 ijuotations submitted for Laboratory Outfit'; or 



Single Instrument.'-. 

 Thermometers for Student Work a Speciality. 



J.Woolley,Sons&C& 



Victoria Bridge, Manchester. 



CATALOGUES ON APPLICATION. ' 



Enlarging Lenses 



must be fitted in plain mounts with metal leaves 

 to the iris diaphragms. Vulcanite such as is used 

 for shutter diaphragms flares up in the lantern. 



.\ Series IV. f/6.3 DALLMEYER STIQ- 

 MATIC (British inadi}^ in enlarging mount 

 gives first-rate results with short exposures. 



The low price allows one to keep this lens 

 specially for enlarging, and avoids the risk of 

 injuring the lens on the camera. 



Its standard iris has metal leaves — they are 

 better. Other makers' lenses have vulcanite. 



Choose a lens for the same size as your negatives. 

 It will give sharp enlargements up to any size. 



i-plate, £3 ; 5 x 4 and P.C, £3 10/- ; 



4 -plate, £4 5/-; 8i X 6J, £7 16/- 



Xew Illustrated Catalogue frei from 



J. H. DALLMEYER, Ltd., 



(Established iStx), 



2, DENZIL WORKS, NEASDEN, LONDON, N.W., 

 and 25, NEWMAN ST., OXFORD ST., W. 



LEITZ' New Microscopes possess many advantages over the older type, ana embody several 

 important features not to be found m any others. The modified horse-shoe base gives greater rigidity, and the 

 larger stage and curved limb additional working space, allowing large size Petri dishes, etc., to be examined with 

 convenience. The new fine adjustment, with an endless motion, is stronger and more durable than the micro- 

 meter screw adjustment, and in the hands of the novice renders breakage of cover glasses and injury to the front 

 lenses of objectives impossible. It enables the expert worker to attain greater speed in focussing, especially with 

 oil immersion objectives. The mechanical features in the new models, combined with the high quality of the 

 recently improved objectives, place the Leitz Microscopes in an unrivalled position. Prices, with optical 

 equipment, from ^^6 10s. E. Leitz, Oxford House, 9, Oxford St., London, W. -Agents in all University Centres. 



" Knowledge " may be obtained through any Bookstall or Newsagent. 

 Offices : — 42, Bloomsbury Square, London, W.C. 



