/ 'i-6-a f 



T1^ T> "El^S. PO* XT 3VX ^ E R, 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



' ' To the solid ground 

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



INDUCTION COILS. 



Messrs. NEWTON & CO., of 3 Flekt Stkeki, London, 

 li.ive niaile an arrangement with Mr. Aits by which the resuUs 

 of his luiequalled experience in large Coil making have been 

 fully 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. Newton & Co. on their own premises. 



These Coils have for many years been acknowledged the best 

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

 quality of workmanship maintained in Messrs. Newton & 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. 



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



)6. — " The Specinl Vacuum Tul; 

 sled in my laboratory wit! 



Mr. a. a. C. SWINTON, April i5. i 

 you recently supplied to me has been 

 satisfactory results.* 



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

 u-i was an excellent one — we have not had a better. Plea<;e send another 



INDUCTION COILS. 



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

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



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

 .Mr .\RNOI,Ii H. Ui.l.^ KTI . I .K.c;.S.. i.;.- ■■ ThcC-il i;ivi,._v,.-L 

 ingly good results, .ind willi its us. 1 h-.,\c taken s..ine spkn.iij, «L-U-Jctin> 

 shadow photographs." 



Excellent definition, any Si2e made to Order. Sizes in stock : 5X5 inche 

 1 SJ. ; 7 X 5 inches, i8j. ; 8 x6 inch es, 22s. 6rf. each. 



NALDER BROS. & CO ., lonoon 

 D'ARSONVAL GALVANOMETER 



Delivered Free anywhere in U.S.A. for -:32 C.O.D. 

 q3^ Write for 



CATALOGUES. 



D'ARSONVAL 

 GALVANOMETER 



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

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

 of Terminals so that they can be used with Primary Batteries or 

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

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

 currents. 



JOHN J. GRIFFIN & SONS, 12 



22 QARRICK STREET, LONDON, W.C. 



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^ 



Scientifc Ins tnim ent 

 Makers to the Queen,. 



38 HOLBORN VIADUCT. 



ranches — 45 Cornhill,, 

 122 Regent Street, 

 London. 



ILLUSTRATED DESCRIPTION POST FREE. 



Telephone No. 6583, Telegraphic Addjess, " Negretii, L 



