67)G.^/^ 



A WEEKLV lLLUi5iRATEI>'j.OURNAL OF SCIENCE. 



** To the solid ground 

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



No. 1687, Vol. 6s] 



THURSDAY, FEBRUARY 27, 1902. 



[Price Sixpence. 



Registered as a Newspaper at the General Post Office.) 



[All Rights are Reserved. 



T.^STyXJCSTTOSff COIX^S. 



APPS" PATENTED INDUCTION COILS are now manufactured 



concurrently by 



:PJ E "SAT T O !«■ AC CO., 



Opticians. &c., to H.M. the King, 



3 r'X.EIlT S^rHEET, j:.O«ri3O3S0'. 



COMPLETE SETS UF APPARATUS FOR RONTGEN "X" RAYS. 



The Set with lo-in. Spark Coil is being used in many hospitals 

 fir the Cure of Lupus. 



ILLUSTRATED CATALOGUE POST FREE. 



X-RAY TUBE 



Special arrangement 

 for the 



REGULATION OF THE 



HEAVY DISCHARGE 

 TUBES 



for use with 



ELECTROLYTIC 

 -> BREAKS. 



Send for our 

 New Price List. 



JOHN J. GRIFFIN & SONS, Ltd., 



20-26 SARDINIA STREET, LINCOLN'S INN FIELDS, 

 LONDON, W.C. 



THE NEW BOOK. 



"PRACTICAL NOTES ON TELEPHOTOGRAPHY." 



50 PAGES, 



BOUND, 



6d. 



50 PAGES, 



BOUND, 



6d. 



THE ABOVE WORK GRATIS ON RECEIPT OF STAMP. 



R. & J. BECK, Ltd., 68 CORNHILL, E.G. 



SPECTACLES 

 ELECTRIC LICHT, INCANDESCENT GAS. 



And other Powerful Illuminants. 



NEGRETTI & ZAMBRA'S 

 THERMOSCOPIC LENSES 



Protect the Eyes from Glare, and 

 RENDER THE LIGHT SOFT AND COOL. 



N. and Z.'s SPORTING SPECTACLES, close-fitting and having extra 

 large lenses, are the best for Billiards, 'Riding, &c. 



Illustrated Price Lists Frit by Post to all parts of the IVorU. 

 Motorists' aid other Eve Protectors and Face Screens. 



NEGRETTI AND ZAMBRA, 

 38 HOLBORN VIADUCT, E.G. 



BRANCHES : 45 CORNHILL ; 122 REGENT STREET. 

 TWO GOLD MEDALS PARIS EXHIBIT ION 1900. 



