Manual of qualitative analysis / by Robert Galloway.

  • Galloway, Robert.
Date:
1861
Catalogue details

Licence: Public Domain Mark

Credit: Manual of qualitative analysis / by Robert Galloway. Source: Wellcome Collection.

    81/272 (page 63)
    the flame of a Bunsen’s lamp. The colours they com- municate to the flame can be increased in intensity, by first putting them into the reducing flame, and then either moistening them with hydrochloric acid, or by holding some asbestos moistened with this acid in the flame directly under the point of the platinum wire on which the substances are supported. They always burn in the following order :— First is seen the green of baryta,next the bright red of strontia, and lastly the dull and scarcely visible red of lime. When, however, a large quantity of strontia or lime is present in proportion to the baryta, the red colours of the two former are observed at the same time; and, in this case, the green of the baryta can only be seen distinctly by passing the wire on which the substance is supported in and out of the flame during the observation. When much lime is present, it modifies considerably the colours of baryta and strontia; so much so, that these two last, when in small proportions, cannot be distinguished. By a_ solution of indigo more dilute than that used for the alkalies, strontia can be distinguished from lime, as through it lime appears olive-green, and strontia intense red, when they are first introduced into the flame, after being moistened with hydrochloric acid. As it is easy to separate the baryta and almost all the strontia from the lime by means of dilute sulphuric acid, and as when only baryta and strontia occur together, they are easily distinguished by the naked eye, when one part of baryta occurs with one hundred parts of strontia, and vice versa, it is best to separate baryta and strontia from lime. 153. The following method answers perfectly for their separation. The carbonates, as usually obtained, are dis- solved in hydrochloric acid, and to the solution, diluted with water, dilute sulphuric acid is added. The sulphates of