Analysis by Spectrum-observations, 103 



2. Mineral waters often exhibit the reactions of potassium, 

 sodium, lithium, calcium, and strontium by mere heating. If, 

 for example, a drop of the Diirkheim or Kreuznach waters be 

 brought into the flame, the lines Na «, Li a, Ca a, and Ca /3 

 are at once seen. If, instead of using the water itself, a drop of 

 the mother-liquor is taken, these bands appear most vividly. 

 As soon as the chlorides of sodium and lithium have been to a 

 certain extent volatilized, and the chloride of calcium has become 

 more basic, the characteristic lines of the strontium spectrum 

 begin to show themselves, and continue to increase in distinct- 

 ness, until at last they come out in all their true brightness. In 

 this case, therefore, by the mere observation of a single drop 

 undergoing vaporization, the complete analysis of a mixture 

 containing five constituents is performed in a few seconds. 



3. The ash of a cigar moistened with hydrochloric acid, and 

 held in the flame, shows at once the bands Na a, Ka a, Li a, 

 Ca a, Ca 0. 



4. A piece of hard potash-glass combustion tubing gave, both 

 with and without hydrochloric acid, the lines Na a and Ka a ; 

 treated with fluoride of ammonium and sulphuric acid, the bands 

 Ca a, Ca /3, and traces of Li a were rendered visible. 



5. Orthoclase from Baveno gives, either alone or when treated 

 with hydrochloric acid only, the line Na a with traces of Li a 

 and Ka a. ; with fluoride of ammonium and sulphuric acid, the 

 bright lines Na a and Ka a, and a somewhat less distinct Li a, 

 are seen. After volatilization of the bodies thus detected, the 

 bead moistened with hydrochloric acid gives a scarcely distin- 

 guishable flash of the lines Ca « and Ca /3. The residue on the 

 platinum wire, when moistened with cobalt solution and heated, 

 gives the blue colour so characteristic of alumina. If the well- 

 known reaction of silicic acid be likewise employed, we may 

 conclude from this examination, made in the course of a very few 

 minutes, that the orthoclase from Baveno contains silicic acid, 

 alumina, potash with traces of soda, lime, and lithia ; and also 

 that no trace of baryta or strontia is present. 



6. Adularia from St. Gothard comported itself in a similar 

 manner, with the exception that the calcium reaction was indi- 

 stinctly seen, whilst that of lithium was altogether wanting. 



7. Labradorite from St. Paul gives the sodium line Na a, but 

 no calcium spectrum. On moistening the fragment with hydro- 

 chloric acid, the lines Ca a and Ca /3 appear very distinct ; with 

 the fluoride of ammonium test, a weak potassium reaction is ob- 

 tained, and also faint indications of lithium. 



8. Labradorite from the Corsican diorite gave similar reac- 

 tions, except that no lithium was found. 



9. Mosanderite from Brevig, and Tscheffkinite from the 



