530 SCIENCE PROGRESS 



and Ag = 107-871. Secondly, the work of Richards and Staehler 

 (32) affords the ratio 



K : CI = 1-102641 



which, combined with Staehler and Meyer's ratio (37) 



KC10 3 : KCl = 1-643819 



leads to the value CI = 35-458. 



The mean value CI = 35-456 derived from these gravimetric 

 results is in agreement with the value 35-461 deduced by Gray 

 and Burt, using the method of limiting densities ; and if Morley's 

 values for the density and atomic weight of hydrogen are 

 admitted, further' confirmation is supplied by Edgar's syntheses 

 of hydrogen chloride (34), which give CI = 35-461 and Gray and 

 Burt's volumetric analyses of hydrogen chloride (20), which give 

 CI = 35-459. It should be mentioned, however, that Noyes and 

 Weber's syntheses of hydrogen chloride (28) supply the dis- 

 tinctly low value 35-452, whilst the analyses of nitrosyl chloride 

 by Guye and Fluss (35) furnish a decidedly high result, 

 viz. 35-466. 



In conclusion, it would appear that the physical methods 

 have led to the deduction of several fundamental atomic 

 weights, which, in point of accuracy, compare favourably 

 with the values derived from the best chemical work that 

 has been accomplished. It is to be hoped that subsequent 

 research will add to their number : as has been already 

 indicated, a considerable amount of work still remains to be 

 done on the subject of gaseous compressibilities. 



References 



1. Rayleigh and Ramsay, Phil. Trans. 1895, 186, A, 187. 



2. LEDUC, Ann. chim. phys. 1898 (vii), 15, 5. 



3. Berthelot, D., Compt. rend. 1898, 126, 954, 1030, 141 5 ; /. de physique, 1899, 



8, 263 ; Zeitsch. Elektrochem. 1904, 10, 621. 



4. Van der Waals, Continuity of the Liquid and Gaseous States, 2nd German 



Ed. pt. i. p. 85. 



5. Guye and Friderich, Arch. Soc.phys. et hist. nat. Geneve, 1900 (iv), 9, 505. 



6. Berthelot, Travaux et Memoires du Bureau des poids et mesures, 1903, 13. 



7. Chappuis, ibid. 1903, 13. 



8. Ramsay and Steele, Phil. Mag. 1903 (vi), 6, 492. 



9. Guye, Compt. rend. 1904, 138, 12 13 ; /. chim. phys. 1905, 3, 321. 



10. Bull. Soc. chim. 1905, 33, 1 ; Chem. News, 1905, 92, 261, etc. 



11. Haentschel, Ann.physik, 1905,16, 565. 



12. Rayleigh, Phil. Trans. 1905, 201, A, 351. 





