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.

    70/272 (page 52)
    121. When soda, potash, and lithia occur together, one part of each can be detected in two hundred parts of the mixture. Assoda in the minutest quantity is visible to the naked eye, we have now a perfect means of detecting the three alkalies in the presence of each other. j22. The following table will show how the detection is effected by Cartmell’s method : With the naked eye. Cobalt glass. Indigo solution. Yellow: Violet-red : Comparative _ test Sank. Poeicn: with pure sulphate of potash. Brighter red than sulphate of potash alone : LITHIA. When the absence of potash has been pre- viously proved by the cobalt glass, red rays visible through the indigo solution prove the presence of lithia. SECOND GROUP. Baryta. Strrontia. Lime. Maanesta. 123. The members of this group are called alkaline earths. They are soluble in water in their pure (caustic) state, also of changes of colour, which the mixed flame produced by these sub- stances experiences when the rays reach the eye, after passing through gradually thicker layers of an indigo solution. For this purpose, Bunsen employs a hollow plate-glass prism, filled with indigo solution: it is 40 millimétres high, and its principal section is a triangle, with two sides of 150 millimétres, and the other of 35 millimétres. Bunsen pre- pares the indigo solution by dissolving 1 part of indigo in 8 parts of fuming sulphuric acid, diluting with 1500 to 2000 parts of water, and filtering. (Consult the account of Bunsen’s blowpipe experiments in the Appendix.)