A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



*' To the solid grointd 

 Of Nature trusts the mimi which builds for ajye." — Wordsworth. 



THE BEATING OF THE HEART , NALDER BROS. & CO ., lonoon. 

 THE MOVEMENTS OF THE DIAPHRAGM D 'A RSON VAL GAL VA NOMETER 



3an be seen by the aid of the Special "Focus" Tubes (25.?. | Delivered Free anywhere in U.S.A. for .?32 C.O.D. 



Mch) and the Fluorescent Screens (35/. each) made by rri3Eti3 



N'EWTON & CO., J Fleet Street, Lo.ndon, if used with ,^ -^ u y-" Write for 



one of their 6-inch Induction Coils. ITi mJ I I CATALOGUES. 



N EWTON & CO., 3 FLEET STREET, LONDON, 



Are now prepared to supply the well-known " Focus " Tubes 



manufactured by them at the reduced price of 25s. each. 



The.se Tubes are still unsurpassed for Rapidity, Brilliancy, 

 and Definition. 



When ordering, the length of Spark to be used, should be 

 mentioned. 



.\11 the Tubes for 6" Spark and upwards will work right 

 through the human body, showing the heart, liver, spine, ribs, 

 movements of the heart, diaphragm, iS;c. 



Customers can .see these Tubes at work at 3 FLEET Street, 

 London. 



NEW FLUORESCENT SCREENS, extremely brilliant, 

 8' 5", 35s. each ; 10 x 8 , 63s. each. 



JOHN J~GRiFFIN"&~SONS, l£ 



22 GARRICK STREET, LONDON. W.C. 

 X-RAY TUBES, " FOCUS " PATTERN. 



A. For Photographic Work miiy, 15s. each. 



B. For Photographic and 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 15 are exhausted for use with 3-inch and 4-inch Spark 



Coils. 

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

 you recently supplied to me has been tested in my laboratory with ver>' 

 satisfactory results." 



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

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



INDUCTION COILS. 



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

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



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

 Mr ARNOLD H. UI.LYKTT, F.R.C.S., &c.—" The Coil gives exceed- 

 ingly gcni results, and with its use I have taken some splendid, well-defined 

 shadow phutographs," 



lExccIlcnt dcrinition, any Size made t" Onkr. Siz«s in slock : 5X5inche>, 

 '5-r- ; 7>^5 inches, iS^^. ; S ■- n iiicho, z.-i". t>tf. each. 



D'ARSONVAL 

 GALVANOMETER 



(As illustr.iled). 



VERY PORTABLE. 



SENSITIVE. 



IN STOCK. 



£5J) 



NO AGENTS 



IN 



U. S. A. 



STTlVLlVIEi e, HOl .ID.A.'yS. 



NEGRETTI & ZAMBRA'S 



BINOCULARS AND TELESCOPES. 



Makers of the "OFFICER OF THE W,\TCH " TELESCOPE, 

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



Nickel-plated, covered with Brown 



Leather. 



PRICE £2 lOs. 



Perfect Dei 



'.\RMY SIGN.'^LLING" TELESCOPE. 



£2 2s. 



£2 2s. 



As supplied by NEGRETTI &. ZAMBRA to the War Office. 



Length, when closed, ii inches. Ccmljiiiing hvib power .ind portahilit\ . 



NEGRETTI & ZAMBRA, 



SCIENTIFIC INSTRUMENT MAKERS to the QUEEN. 



38 HOLBORN VIADUCT, E.C. 



Branches: 45 CORNHILL; 122 REGENT STREET. 



L.i.usrii.MEU PKlCb Lis;s Full, ]iv I'u.si. 



