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.

    69/272 (page 51)
    evaporated to dryness, and the residue treated with cold water, the basic phosphate remains undissolved. We can therefore in this way distinguish lithia from, and in the presence of, potash and soda. 119. “If a salt of lithia (more particularly chloride of lithium) is exposed on a platinum wire to the inner blow- pipe flame, the outer flame shows a strong CARMINE tint. Presence of salts of soda (but not salts of potash) conceals this reaction.” 120. Cartmell has found that when the coloured rays produced by burning soda, potash, and lithia, in the blow- pipe flame, are transmitted through a solution of indigo, the yellow-coloured rays from the soda are obliterated, whilst the red rays from lithia and potash pass freely through the solution. When potash is absent, the indigo solution* gives a means of rendering visible the red rays from lithia in the presence of soda, when the proportions do not exceed one part of the former to a thousand parts of the latter. The presence of lithia can be detected in that of potash, or of potash and soda, in the following way :—Place side by side in the flame two platinum wires, one having on its point a little pure sulphate of potash, and the other the sample to be tested. If there be lithia in the sample to the extent of one part to two hundred parts of potash, a very marked difference will be seen between the colour of the two flames,f that containing lithia being of a much brighter red. * Cartmell prepares the indigo solution by adding water to the common indigotic acid of the laboratories, till the point is all but reached, when an intense flame of soda appears slightly pink, when observed through the bottle (of the size and shape of a common watch) filled with the solution. tT Bunsen has found that the discrimination of these bodies in pre- sence of each other is more easily effected by observing the succession