KNOWLEDGE. 



October. 1910. 



THE "STUDENT'S " 



Extra HighTensionl STANDARD Barometer. 



We have now installed a COMPLETE 

 AND POWERFUL PLANT giving a 

 peak voltage of 



84,000 Volts 



and are open to TEST Apparatus 

 or MANUFACTURE such up to that 

 voltage. 



Enquiries Solicited. 



ISENTHAL & Co. 



I Department 2 , 



85, Mortimer Street, London, W. 



Coutraciors to the Admiralty^ War, 

 India, and Colonial Offices, i^c. 



MICKOSCOPES AND SLIDES. 



N 

 T 

 E 

 R 



N 



FLATTERS &GARNETT 



Ltd. 



32, Dover Street, 

 MANCHESTER, S.E. 



Note the above, our only address — 

 no connection with anv other finn. 



DELICIOUS COFFEE. 



RED — 

 WHITE 



& 



BLUE 



For Breakfast & after Dinner. 



In making, use less Quantity, it being much stronger 

 than ordinary Coffee. 



^^- 



(Ke^iitcrt\i Desist Xo. 420, 2Q-). 



Designed to meet the requirements of Students and others who find 

 the need of a Harometer which wHt give exact readings, and cost 

 but a moderate sum. 



^ Used for demonstration purposes in all the principal 

 Science and Technical Colleges, and adopted by the L.C.C. 

 for use in their Classes. 



The construction is on that of the well-known '*Fortin" principle. 

 The level of the ci^te^n mercury is reducible to zero, in exactly the .same 

 manner as in the more expensive forms. The diameter of the mercurial 

 column is '25 inch, and affords a bold, well-defined reading. The scales, 

 by means of the double vernier, are capable of being read to "01 inch 

 and 'I millimetre. It is mounted on a wcll-polished, solid oak or 

 mahogany l)oard, with opal glass reflectors for reading off, and screws 

 for vertical adjustment. The metal portions are all well bronzed and 

 lacquered, and the scales are opal glass. A thermometer, graduated on 

 stem F. and C. scales, is fitted to the brass frame. 



We confidently recommend this Instrument for use as a " Standard " 

 in Colleges and Schools, private Observatories, and by (Jas and other 

 Engineers. 



PRICE, complete, mounted as illustrated, 



£3 7 6. 



VW Natl KK sajs ; — '' Provides an accurate instrument at a moderate 



Li3St." 



GLAZED CASE (Oak or Mahogany) with lock, to contain above 

 r.aronieier, £1 2 6 



FULL SIZED STANDARD BAROMETER of same design, 

 bore 0*5" diameter, iriches and millimetre scales, verniers reading to 

 0*002 inch and o'l mm, on polished oak or mahogany board with 

 brackets and opal glass reflectors, £7 10 O 



Sole Manufacturers and Propriet0rs of the Regd. Design : 



PASTORELLI & RAPKIN, LTD. 



(ESTAB. 17501. 

 Actual Makers of all kinds oj Meteorological Instruments. 



CONTKACTOR^ TO H.M. ('.0\ERNMENT. 



46, HATTON GARDEN, LONDON, E.G. 



STANDARD INSTRUMENTS OF ALL KINDS. 



im~ ILLUSTRATED PRICE LISTS POST FBEE. 



*_* We p:^y carriage and guarantee safe delivery within U.K. on all 

 our Instruments. 



SECONDHAND 



MICROSCOPES AND APPARATUS. 



Seccmdh.^iKi Army Bacteriological Microscope, by 



J. Swift & Son, titled with .\bbe condenser and iris diaphragm. 



:ind 



oil 



triple nosepiece, eyepiece, mechanical stage, 

 immersion objectives, £14 I4s. Od. 



Secondhand 2 mm. Holoscopic Oil Immersion Objective, 

 by Watson & Sons, £6 6s. Od. 



.Second-hand 4 mm. ditto, £2 18s. 6d. 



The Largest Stock in London of Secondhand Microscopes and 

 Objectives by all the leading malcers, comprising Outfits suitable 

 for Histology, Bacteriology, Botany, and all branches of Science. 

 A comprehensive selection o( Microscopic Objects, including Geological, 

 Botanical, Anatomical, Minerals, Diatoms, Insect parts, &c., at 6d. each. 

 Second-hand I'rism Binocular Glasses, by Zeiss, Goer:, A'oss, and 

 other makers, in perfect condition. 



Ca/alo^ites post free oil applieation. 



MILL! KIN & LAWLEY, ^S^ndInI'^^'c 



Telephone-city 1706. 



Typewriters 



MSS. Copied. 



Bought, Sold, Repaired, 

 and Exchanged. 



Hire . . lOs. a Month 

 or 27/6 a Quarter. 



^Dept, 



TAYLOR'S, Ltd.,( 



74, CHANCERY LANE, LONDON, W.C. 



Printed for (he Proprietors (Knowledge Publishing Company, Limited), by JOHN King, Ealing and U.\bridge.— October, 1910. 



