vS oo>vc 



A WEEKLY ILLUSTRATED JOURNAL OF SCIENXE. 



" To the solid ground 

 Of Nature trusts the mind which builds for a;,«."-W0RDSWORTH. 



'^^^;^^e67^^^0u6A\ THURSDAY, OCTOBER lo, 1901. 



[Price SIXPE^•CK. 



tAll Right! 



NEW DOUBLE-POLE (NEWTONIAN) MOTOR 

 MERCURY BREAK. 



A NEW 

 LENS 



v' 



# 



ru 



KOR ALL 

 WORK. 



In 3 Series. 

 I. GEN'ER.\L. 

 II. CO.NVtRTlBLE. 

 III. SEECIAL PROCKS? 





IW B ^W T O IV «Se CO 



OPTICIANS. Ac. TO HIS MAJESTY THE KING. 



Q FT. RET STREET. LONDON. 



X-RAY TUBES. 



Special arrangement M,^ 



for the f i\ 



REGULATION OF THE 



'4^ HEAVY DISCHARGE 

 TUBES 



for use «ith 



ELECTROLYTIC 

 > BREAKS. 



Send for our 

 New Price List. 



This rapid, wide, medium or narrow angle lens all in one is 



suitable for all work 



Full Catalogue free on applicaf-on w the .Manufacturers :- 



R. Sc J. BECK, I-ta., 



€8 CO RNHILL, LONDON, E.G. 



SPECTACLES 

 ELECTRIO LIGHT, INCANDESCENT GAS. 



And other Powerful Illummants. 



JOHN J. GRIFFIN & SONS, Ltd 



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

 LONDON, W.C. 



NEGRETTI & ZAMBRA'S 

 THERMOSCOPIC LENSES 



Protect the Eyes fioni Glare, and 



RENDER THE LIGHT SOFT AND COOL. 



N and Z.'s SPORTING SPECT.A.CLES, close.fitt.ns and hav.ng e.xt,a 



N E G R ETTl and ZA M B R A, 

 38 HOLBORN VIADUCT, E.G. 



