v-^ 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



' ' To the solid ground 

 Of Nature trusts the mind which builds for aj-s."— Wordsworth. 



No. 1 40 1, Vol. 54] 



THURSDAY, SEPTEMBER 3, 1896. 



[Price Sixpence. 



Newspaper 



General Post Office.] 



INDUCTION COILS. 



Messrs. NEWTON & CO., of 3 Fleet Street, Londox 

 have made an arrangement with .Mr. .^pps by which the results 

 of his unequalled experience in large Coil making have been 

 Jully placed at their disposal. 



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

 instruments, Apps' Patented Coils are now manufactured con- 

 currently by Messrs. New rev & Co. on their own premises. 



Ihcse Coils have for many years been acknowledged the best 

 and most efhcient m 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 



All the Coils up to jo-inch are tested to considerably more 

 .han the guaranteed length of spark 



tpark i 

 I in. 



3 >. 12 12 



4 .. 15 15 



6 ,, (with pillars) 22 10 



.Sp.irk in air. / 



8 in. (with pillars) 27 

 1° .. „ „ 36 

 '5 >. ,. „ 63 

 ■8 .; .. ... 75 - 

 l^arger sizes to order. 



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

 iighest qua ity, and all are fitted with Commutator and five pairs 

 il lerminals .so that they can be used with Primary Batteries or 

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

 ut out if desired, which should be done when using alternate 

 urrents. ° 



NALDER BROS. & CO., london 

 D'ARSONVAL GAU'ANOMETEfi 



Delivered Free anywhere in U.S.A. for 832 C.O.D. 



JOHN J. GRIFFIN & SONS. l£ 



22 GARRICK STREET, LONDON, W.C. 

 C-RAY TUBES, "FOCUS" PATTERN. 



. For Photographic Work only, I5s. each. 



. For Photographic and Screen Work, 25s. each. 



. For Photographic an,i Screen Work, e.xhausted for 



use with Colls giving 6-inch Sjiark and upwards, 35s. each 

 '^Coils^ "" *''*'^"^'*'' ^'" ""*= "'"^ 3-inch and 4-inch Spark 



m^Lt^.JnP^J^^- ^P"'.'^' 'SsS-'-.The Special Vacuum Tube 

 i"sfictorl'*rru^!l ■• "■* ""^ ''"" "=""' '" "y '^boratory wi.h verj- 



wT,„"^"-'^i'7?'='^' ""'r^i'y College, Rristol -"The tube you sent 

 Dn^s you ic aUc°" ""*' "°' '""' " '""'"" ^'°^''"' *^"'' *"°'h<:r =»s 



INDUCTION COILS. 



3in., £9; 4-in., £12; 511,., £15; 6in., £18. 

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



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

 Mr. ARNOLD H. UI.LVETT, F.K.G.S., &c.-" The Coil gives exceed- 



cellent dt-lm.t.cn, .-.ny Size n,.-,de l., Order. Si.ces in s.ock : 5, •< 5 inches 

 ■ ,ss. ; 7 X 5 inches, iSi. ; 8x6 inches, 22s. M. each. 



Write for 

 CATALOGtJES. 



D'ARSONVAL 

 GALVANOMETER 



(As illustr.ited). 



VERY PORTABLE. 



SENSITIVE. 



IN STOC-K. 



£5^ O 



NO AGENTS 



IN 



U. S. A. 



NEGRETTI ^ZAMBRA'S 



BINOCULARS AND TELESCOPES. 



.M.ikers of the "OFFICER OF THE WATCH" TELE.SCOPE, 

 in u.^ic on all the vessels of H.M. Na 



Nickel-plated, covered v\ith 

 Leather. 

 PRICE £2 IDs. 



Perfect Definition & High Power. 



£2 2s. 



£2 2s. 



As supplied by NEGRETTI & ZAMBRA to the War Office. 



Length, when clo.sed, 11 inches. Combining hi^h power and portability 



NEGRETTI & ZAMBRA, 



SCIENTIFIC INSTRUMENT MAKERS to the QUEEN. 



38 HOLBORN VIADUCT. E.G. 



Branches : 45 CORNHILL; 122 REGENT STREET. 



iLLtb 



Flilcb Lj: 



