ccliv 



NATURE 



[October 26, 1905 



f 



All other air 

 pumps superseded. 



THE. 



"GERYK" 



(rieuss Patent) 



Vacuum Pump. 



R.esults hitherto only pos- 

 sible ^vith mercury pumps 

 are readily obtainable by 

 the " GeryR." Used by 

 all leading scientists. Far 

 more rapid than any other 



vacuum pump. 

 Price from Write for 



84 : 5 : 0. LIST F.45. 



putoORietet engineering G^Cf 

 " CBMebMinDwoTHi. Reading. 



REYNOLDS & BRANSON, Ltd 



Chemical and Scientific 



Instrument Makers, Laboratory 



Furnishers & Manufacturing 



Chemists. 



Special Apparatus 



for 

 Consterdine and 



Andrews' 

 " Practical 



Arithmetic." 



Set "A," 



130 MODELS, 



30,- 



Set "B," 



70 MODELS, 



20/- 



DESCRIPTIVE LIST POST FREE. 



14 COMMERCIAL STREET, LEEDS. 



SELF-REGISTERING 

 SELF-RECORDING 



(ELECTRICAL) 



RAIN 

 GAUGES. 



THE 'WILSON' 



SELF-REGISTERING 



RAIN GAUGE. 



If any difficulty be found 

 through your Dealer kindly 



PASTORELLI 



The 'WILSON' 



SELF-RECORDING 



ELECTRICAL 



RAIN GAUGE. 



Records auto- 

 matically on a 

 Weekly Chart. 



AfAV BE OBTAINED THROUGH AXV OPTICIAN. 



(Established 1750), 



RAPKIN, 



Contractors to H.M. Government^ 



46, HATTON GARDEN, LONDON, E.G. 



Telephone No. igSi, Holborn. Telegrams— "Rapkin, London." 



Actual i Wholesale) Makeds of all kinds of Meteorolocigal Instruments. 



SALTS OF 



PURE RADIUM 



AND RADIO ACTIVE SALTS OF ALL STRENGTHS. 



All the Salts are absolutely guaranteed ; they 

 are prepared according to the methods used 

 by M. Curie, and are standardised witl| 

 his instruments by his assistant, M. Danne. 



VARIOUS RADIO-ACTIVE SUBSTANCES. 



Polonium. Actinium. 

 Pure Salts of Uranium and Thorium. 

 Radio-active Emanations. 

 Radio-active Liquids and Substances tested. 



PHOSPHORESCENT SUBSTANCES. 



Sulphide of Zinc. Tungstate of Calcium. 



APPARATUS FOR PHYSICAL AND MEDICAL APPLICA- 

 TION OF SALTS OF RADIUM. 



ADMCT nC llOICf Factory at NOCENT-SUR-MARNE. 

 HnlVILI Ut LIOLC \ Offices: 13 RUE VICNON, PARIS. 



