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V. The Atomic Weight of Chlorine: An Attempt to determine the Equivalent 

 of Chlorine by Direct Burning with Hydrogen. 



By HAROLD B. DIXON, M.A., F.R.S. (late Fellotv of Balliol College, Oxford), 



Professor of Chemistry, and E. C. EDGAR, JB.Sc,, Dalton Scholar 



of the University of Manchester. 



Received May 18, Head May 18, 1905. 



CONTENTS. 

 PART I. GENERAL. 



PART II. DETAILS OF EXPERIMENTS. 



Page 



1. Preparation of hydrogen 172 



2. The palladium bulb 175 



3. Preparation of chlorine 177 



4. The chlorine bulb 180 



5. Preparation of reagents 181 



6. Weighing the bulbs 185 



7. Method of carrying out the combustion 189 



8. Results of the experiments 195 



Appendix ... .198 



PART I.- GENERAL. 



SOME apology seems needed in presenting a new research on the atomic weight of an 

 element already measured with a precision which the highest living critic has 

 emphasised as " the magnificent accuracy of STAS' determination." 1 * Moreover, the 

 present experiments cannot claim an accuracy to be compared with any individual 

 series of STAS' ratios. But, on the other hand, STAS' atomic weight of chlorine is 

 derived indirectly from oxygen by a series of operations which include the deter- 

 mination of (1) the oxygen in potassium chlorate, (2) the silver equivalent to the 

 molecule of potassium chloride, and (3) the composition of silver chloride. STAS 

 himself has assigned different values to these ratios at different times ; e.g., in 1860 he 

 found that 100 parts of silver were equal to 69'103 of potassium chloride, in 1882 he 



* F. W. CLARKE, 'A Recalculation of the Atomic Weights.' New edition. 1897, p. 57. 

 VOL. CCV. A 391. Z 24.8.05 



