/ 



^V»* / 'Z § 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



** To the solid ground 

 Of Nature trusts the mind which builds for aye.'''' — Wordsworth. 



X-RAY "FOCUS" TUBES. 



The '* Focus" Tubes made by Newton" & Co., in accordance 

 with the experiments conducted in the Chemical Laboratory at 

 King's College, are still unequalled for rapidity and definition. 



Price 30s. each. 



The above are suitable for Coils giving 2" spark and over. 



Special '* Focus" Tubes, 42s. each. 



The above are suitable for Coils giving from 7" to 10" sparks. 



'* The definition given by your focus tubes is e,vcellent."— Prof. Oliver 

 J. Lodge, Unir'ersity Cotlege, Liverpool, 



" Your focusing lube has worked very well, and as soon as you have 

 another similar one that you can spare me I shall be glad to have it." — 

 Prof. A. Schuster, The Owens College, Manchester. 



*' We have got excellent resuhs with the focus tubes." — Prof. W. 

 Heaton, University College, Nottinghain. 



'* The focus tube you sent gives remarkably sharp shadows." — Prof. A. 

 S. Butler, The Unri»ersity, St. Amirews, N.B. 



'* 1 have tried a very large number of vacuum tubes sold by different 

 makers for the purpose of giving the X-rays, and find your ' focus tubes ' to 

 be far and away superior to anything as yet in the market." — Prof. W. F. 

 Barrett, Royal College of Science, Dublin. 



" Les r^sultats sont merveilleux."— Dr. Henri van Heurck, Jardin 

 Botanique d'Attvers. 



Sole Makers : 

 ^T IS "\^r T O ]N^ ^C CO. 



3 FLEET STREET, LONDON. 

 Helium and Argon Spectrum Tubes No^v Ready .^ 10s, 6d. each. 



J OH N^jTORllFFIilNr ATSONS, 12 



22 GARRICK STREET, LONDON. W.C. 



X-RAY TUBES, "FOCUS" Pattern, 27/6 each. 



Mr. a. a. C. SWINTON, April 18, 1896.-" The Speci.il V.icuum Tube 

 you recently supplied to me has been tested in my l.iboratory with very 

 satisfactory results." 



Prof. CHATTOCK, University College, Bristol.— " The tube you sent 

 Uj, was an excellent one — we have not had a better. Please send another .is 

 soon as you are able." 



INDUCTION COILS. 



3-in., £9; 4-in., £12; 5-in-. £15; 6in., £18. 

 Our own Manufacture, as supplied to " The Lancet," 



Shelford Bidwell, Esq., M.A., F.R.S., and others. 

 Mr. ARNOI.U H. ULLYK TT, F.R.i;.S., &c.— ■■ The Coil gives excx. 

 ingly good results, and with its use 1 h.ive t.iken some splendid, well-derim 

 shadow photographs." 



Excellent definition, any Size made to Order, Sizes in stock : 5x5 inch<; 

 1 5.5-. ; 7x5 inches, i8j. each. 



NALDER BROS. & CO., 



LONDON. 



N. C. S. 

 THOlVtS OlV 



REFLECTING 

 GALVANOMETER. 



5000 OHMS RESISTANCE. 



VERY SENSITIVE. 



PRICE 

 ■Write for CATALOGUES. 



Cable Address : 



SECOHM, LONDON 



No Aat-nls ill U.S.A. 



This instrument delivered Free anywhere in U.S.A. 

 for .*60 C.O.D. 



NEGRETTI & ZAMBRA, 



SOLE MAKERS OF 



JORDAN'S (PATENT) SUNSHINE RECORDER. 



New Simplified Model, 

 adjustable for any 

 latitude, and tho- 

 roughly efficient. 

 Price £1 7s. 6d. 



Sensitised Charts, 

 5s. per 100. 



NEGRETTI 

 ZAMBRA, 



Scientific Instrument 

 Makers to the Queen, 



38 HOLBORN VIADUCT. 



Branches— 45 CoRNHlix, 



ILLUSTRATED DESCRIPTION POST FREE. 



Telephone No. 6583. Telegraphic Address, " Negretti, Londo 



