A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ^-ound 

 Or Nature trusts the mind which builds for aye." — Wordsworth. 



No. 1403, Vol. 54] 



THURSDAY, SEPTEMBER 17, il 



[Price Sixpence. 



Registered 



Newspaper at the General Post Onice.) 



INDUCTION COILS. 



Messrs. NEWTON & CO., of 3 Fi.i..et Street, London, 

 tiavf made an arrangement with Mr. Ari'S by which the results 

 if his unequalled experience in large Coil maUing have been 

 fully placed at their disposal. 



As he has been unable to cope with the demand for these 

 instruments, Apps' Patented Coils arc now manufactured con- 

 :urrently by Messrs. Newton & Co. on their own premises. 



These Coils have for many years been acknowledged the best 

 Jnd most efficient in the world, and it is hoped that the high 

 quality of workmanship maintained in Messrs. Newto.N" &Co.'s 

 Workshops may still further increase their reputation. 



.\11 the Coils up to lo-inch are tested to considerably more 

 than the guaranteed length of spark. 



All the .above Coils are covered in ebonite, and are of the 

 highest quality, and all are fitted with Commutator and five pairs 

 r)f Terminals so that they can be used with Primary Batteries or 

 Accumulators or direct from the main, and the Condenser can be 

 :u! out if desired, which should be done when using alternate 

 currents. 



JOHN J. GRIFFIN & SONS, 12 



22 GARRICK STREET, LONDON, W.O. 

 X-RAY TUBES, " FOCUS " PATTERN. 



A. For Photographic Work only, 15S. each. 



B. For Photographic -ind Screen Work, 25s. each. 



C. For Photographic and Screen Work, exhausted for 



use with Coils giving 6-inch Spark and upwards, 35s. each. 

 A and B are exhausted for use with 3-inch and 4-inch Spaik 



Coils. 

 Mb. a. a. C. SWINTON, April 18, 1896.— "The Special Vacuum Tube 

 you recently supplied to me has been tesled in my laboratory with verj- 

 witisfactorv results," 



Pkop, CHATTOCK, University College, Bristol —"The tube you sent 

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

 soon as you .-\re able." 



INDUCTION COILS. 



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

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



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

 Mr AKNOI.DH. UI.I.YETT, K.K.G.S., &c.—" The Coil gives exceed- 

 ingly good results, .-inj with its u-e 1 liave taken some splendid, well-defined 

 shadow pliutographs." 



Fr.xTOREScx:piTrr scxkeekts. 



Excellent definition, any Size m.-ide to Order. Sizes in stock 15X5 inches, 

 '5*. : 7X5inches, iSj. ; 3x6inches, 22j. (^d. each. 



NALDER BROS. & CO., 



LONDON. 



N. C. S. 



"rxxoivEso^ 



REFLECTING 

 GALVANOMETER. 



5000 OHMS RESISTANCE. 



VERY SENSITIVE. 



PRICE 



Write for ICATALOGUBS, 

 Cable Address 



SECOHM, LONDON. 



IVo AgenlH in U.iii.A. 



STJIVElVt Eie. ^oi .iD.A."srs. 



NEGRETTI & ZAMBRA'S 



BINOCULARS AND TELESCOPES. 



Mak.=rs of the "OFFICER OF THE WATCH" TELESCOPE, 

 in use on all the vessels of H.M. Navy. 



£2 2s 



£2 2s, 



As supplied by NEGRETTI & ZAMBRA to the War OfTice. 



Length, when closed, n inches. Comhinin^ Iii:;h pouer and portability. 



NEGRETTI &. ZAMBRA, 



SCIENTIFIC INSTRUMENT MAKERS to the QUEEN, 



38 HOLBORN VIADUCT, E.C. 



Branches: 46 CORNHILL; 122 REGENT STREET. 



Illl-str.\ted Price Lists Fi-iiitc lv Post. 



