386 Browning — Separation and Detection of Strontium. 



Although, the last formula is somewhat novel, it is not 

 altogether improbable; but between it and its alternative we 

 cannot yet certainly decide. Another open question is fur- 

 nished by the chlorites, in which the formation of spinel may 

 possibly be due to the presence of AlOJVIg groups. Upon this 

 supposition, however, the chlorites do not reduce to simple for- 

 mulae, and therefore the suggestion has slight value. Apart 

 from all theoretical considerations, the spinel reaction, as it 

 may fairly be called, is one of an entirely new order in mineral 

 chemistry, and it opens up a noteworthy line of attack upon 

 the difficult problems before us. 



Laboratory XL S. Geological Survey, Washington, Jan. 14, 1892. 



Art. XLYII. — On the Qualitative Separation and Detection 

 of Strontium and Calcium by the Action of Amy I Alcohol 

 on the Nitrates ; by P. E. Browning. 



[Contributions from the Kent Chemical Laboratory of Yale College, XIII.] 



■ In a recent paper* I have shown that strontium and cal- 

 cium may be separated quantitatively by boiling the nitrates 

 of these elements with amyl alcohol and applying the correc- 

 tions determined for the solubility of the strontium salt. The 

 qualitative separation, however, is somewhat vitiated by the 

 deposition of a slight residue upon the bottom of the test tube 

 or beaker when calcium nitrate is boiled with amyl alcohol. 

 While this deposit weighs but a few tenths of a milligram and 

 is insignificant in its effect upon the interpretation of the 

 quantitative results, it may easily be mistaken for strontium in 

 the qualitative test unless tested spectroscopically. This resi- 

 due when dried, dissolved in water and nitric acid, and again 

 treated with amyl alcohol is not dissolved completely but again 

 separates out wholly or partially. The possibility of the forma- 

 tion of the calcium salt of an organic aeid by the action of the 

 nitric acid on the amyl alcohol (a point to which reference was 

 made in the paper before mentioned), suggested the idea that 

 ignition might so change the residue that it would not re-appear 

 upon a second boiling with the amyl alcohol. Experiment 

 proved the truth of this presumption ; for it was found that 

 after getting the ignited residue into solution with water and a 

 drop of dilute nitric acid, subsequent boiling with amyl alco- 

 hol effected complete solution, as shown by experiments (1), 

 (2), (3), (4) of Series I below. In applying the method quali- 

 tatively, small amounts of the amyl alcohol may be conveniently 

 used and the boiling carried on in a test tube, care being taken 



* This Journal, vol. xliii, p. 50. 



