RICHARDS. — ATOMIC WEIGHT OP STRONTIUM. 



371 



Ratio of anhydrous strontic chloride to silver : 



Pelouze, 1845 87.70 



Marignac, 1858 87.48 



Dumas, 1859 87.53 



Ratio of crystallized strontic chloride to silver : 



Marignac, 1858 87.52 



From the crystal water iu strontic chloride : 



Marignac, 1858 87.35 



Ratio of anhydrous and crystallized strontic chloride to strontic 

 sulphate : 



Marignac, 1858 87.2 to 87.6 



Selected by Clarke 87.58 



Selected by Meyer and Seubert 87.5 



Selected by Ostwald * 87.5 



A critical review of the list reveals a great lack of trustworthiness 

 in all the figures. The values deduced from the carbonate, and those 

 involving water of crystallization, may all be thrown out at once ; 

 and the results yielded by the displacement of hydrochloric by sul- 

 phuric acid are but little better. The series upon which most chemists 

 have relied — the one based ou the titration of the chloride by means 

 of silver — is hopelessly vitiated by the imperfect execution of the 

 method of analysis.f If any further proof of this uncertainty were 

 needed, the following table, giving a comparison of the work of differ- 

 ent experimenters upon other chlorides, would furnish it. 



Molecular Weights of Chlorides by the Method of Gat-Lussac. 



* Much assistance in preparing this list has been obtained from the well 

 known works of these authors. The figures have all been based upon the 

 most recently accepted atomic weights. 



t Tliese Proceedings, XXIX. 80 et seq. 



