P. E. Browning — Quantitative separation of Barium. 459 



The analyses were made by W. F. Hillebrand of the U. S. 

 Geological Survey. It will be noted that the two basalts, so 

 different in age and in habitus, are quite similar in composition. 

 As would be expected in the dense black older basalt contain- 

 ing a large amount of magnetite, the iron contents are much 

 greater "than in the coarse-grained gray basalt of later age. 



Washington, D. C, Sept. 9, 1892. 



Art. LXI. — A Method for the Quantitative Separation of 

 Barium from Strontium by the action of Amyl Alcohol 

 on the Bromides ; by Philip E. Browning. 



[Contributions from the Kent Chemical Laboratory of Yale College — XIX.] 



The existing methods upon which dependence can be made 

 in the separation of barium from strontium are few in number. 

 Dr. R. Fresenius in discussing them through several numbers 

 of his journal* concludes that the only one which gives per- 

 fectly reliable results consists of the precipitation of the 

 barium by a double treatment with ammonium chromate in 

 acetic acid solution. Having demonstrated the possibility of 

 separating both barium and strontium from calcium by the 

 dehydrating and appropriate solvent action of boiling amyl 

 alcohol on the nitratesf.the possibility of a similar method of 

 separation by the use of suitable salts of barium and strontium 

 seemed worthy of investigation and necessary to complete the 

 series as applied to this group. In looking about for suitable 

 salts upon which to experiment the behavior of the chlorides 

 was suggestive. Barium chloride is completely insoluble in 

 amyl alcohol while the corresponding strontium salt is some- 

 what soluble. The possibility of finding strontium bromide 

 more readily soluble than the corresponding chloride seemed 

 worthy of attention. The method of preparation followed was 

 the treatment of the precipitated and thoroughly washed car- 

 bonates of barium and strontium with hydrobromic acid pre- 

 pared:}: by mixing definite proportions of potassium bromide 

 in solutions with sulphuric acid and water while hot, filtering 

 off the potassium sulphate which separates on cooling, and re- 

 distilling the filtrate until the distillate contains no appreci- 

 able trace of sulphuric acid. The standards of the solutions of 

 barium and strontium bromides made in this way were deter- 

 mined by precipitating definite portions, measured and weighed, 

 with sulphuric acid, — the strontium after the accepted method 

 of adding ethyl alcohol to increase the insolubility and the 



*Zeitschrift fur Anal. Chem., xxix, 20, 143, 413. 



f This Journal, xliii, 50, 314. ^Proceedings Amer. Acad., xvii, 30. 



