The use of the blowpipe, in the qualitative and quantitative examination of minerals, ores, furnace products and other metallic combinations / Edited, with emendations, by Dr. Sheridan Muspratt. With a preface by Baron Liebig.

  • Karl Friedrich Plattner
Date:
1850
Catalogue details

Licence: Public Domain Mark

Credit: The use of the blowpipe, in the qualitative and quantitative examination of minerals, ores, furnace products and other metallic combinations / Edited, with emendations, by Dr. Sheridan Muspratt. With a preface by Baron Liebig. Source: Wellcome Collection.

    118/440 (page 94)
    that the potassa and oxide of nickel glass is blue, while the oxide of nickel and soda glass is brown. When substances, for instance native silicates, contain only traces of potassa, the above method cannot with cer¬ tainty he resorted to; therefore, the moist way must also be applied, as subsequently described : 50 to 75 milligrammes of the fine powdered body are mixed with twice their volume of soda, and pressed into a cavity in a plate of charcoal, and smelted in the oxidating flame ; if much magnesia or lime is present, the assay will fuse with difficulty. The ignited mass is now removed from the support with the platinum pincers, and any adhering carbonaceous matter burnt away. The mass is pulverized between paper in an agate mortar, then treated in a porcelain basin with hydrochloric acid, and evaporated to dryness over the flame of the lamp. Water is now added, to dissolve the formed metallic chlorides, and, after some time, the solution is poured from the undissolved silica into another basin. This liquid is evaporated until it becomes highly concentrated, and then a few drops of an alcoholic solution of chloride of platinum and sodium are added. If potassa is present, the double salt of chloride of platinum and potassium, which is insoluble in alcohol, will precipitate as a lemon yellow powder. If there is only a small quantity of alkali present, the precipitate will not be perfectly visible for some minutes.^ In combinations of sulphuric acid, which contain both potassa and soda, — as, for instance, Tolyhallite, — it is only requisite to reduce on charcoal the sulphate to a sulphide, and treat with hydrochloric acid, water, &c., as in the previous example. By the preceding methods, one per cent, of potassa in silicates, and other substances, can he recognized. Berzelius has given a similar examination, in one of his treatises upon the quantitative separation of potassa from soda. * [The presence of organic matters does not prevent this reaction.] —Ed.