6 6^,c(:i_ 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENCE. 



" To the solid ground 

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



No. 1677, Vol. 65] THURSDAY, DECEMBER 19, 1901. 



[Price Sixpence. 



L Newspaper at the General Post Office.] 



[All Rights are Reserved. 



STEREOSCOPIC ILLUSTRATIONS 



OF THK THEORY OF 



THE POLARISATION OF LIGHT. 



Set of Paper Stereo Diagrams with description, " The Plane 

 Polarisation of Light," by Charles E. Benham/ 5S. 



SOLE AGENTS: 



"DS E ATV T O »r «SB C O., 



OPTICIANS &e., TO THE KING, 

 3 FLEET STREET, LONDON. 



X-RAY TUBES. 



Special an-angenient 

 for the 



THE NEW BOOK. 



"PRACTICAL NOTES ON TELEPHOTOGRAPHY. " 



50 PAGES, 



BOUND, 



6ci. 



50 PAGES, 



BOUND, 



6d. 



REGULATION OF THE 



HEAVY DISCHARGE 

 TUBES 



for use with 



ELECTROLYTIC 

 >- BREAKS. 



Send for our 

 New Price List. 



THE ABOVE WORK GRATIS ON RECEIPT OF STAMP. 



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



NEGRETTI & ZAMBRA'S 



^ SELF-RECORDING 



METEOROLOGICAL INSTRUMENTS. 



THE THERMOGRAPH, for Outdoor or Indoor Observation. 



This Instru- 



JOHN J. GRIFFIN & SONS, Ltd., 



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

 LONDON, W.C. 



' Special ' 



Accurate Thermometers for all purposes. 



Illustrated Price List of Instruments, si 



Presents, free by Post. 



itable for 



NEGRETTI & ZAMBRA, 

 38 HOLBORN VIADUCT, EC. 



Br.anches— 45 Cornhii.i., and 122 Regent Street, 



AWARDED TWO GOLD MEDALS PARIS EXHIBITION 1900. 



V:^ 



