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.

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    577. While the bead of borax is still hot, it is touched with a small quantity of the powder of the substance under examination, and that which adheres is fused into it. The operator must then observe—Ist, whether the substance is soluble or insoluble in borax; and 2nd, the colour of the borax bead in (1) the oxidizing flame and (2) in the reducing flame, both in the hot and in the cold state. In performing this experiment, care must be taken not in the first instance to dissolve up too large an amount of the oxide or other substance under examination. If a small quantity afford no distinct reaction, more may be easily added. If, how- ever, the colour of the bead be too intense to be clearly distinguished, the bead may be jerked off the wire, and that which still adheres fused up with a fresh quantity of borax, by which a paler and more transparent glass will be obtained. 578. TREATMENT WITH PRoroniTRATE OF CoBaLt.—No explanation beyond that given in the table is required. 579. If the substance should be a metal or an alloy, the only blowpipe experiments which need be made are—lIst, in the glass tube closed at one end; 2nd, as regards its mal- leability ; and 3rd, heating a portion of the substance on charcoal in the reducing flame of the blowpipe. 580. When the student has completed the different preliminary experiments, he will be able to arrange the substance under one of the three following divisions: 581. The solid substance under examination is neither a pure metal nor an alloy, and is destitute of organic matter. 582. The solid substance under examination is neither pure metal nor an alloy, but contains organic matter. 583. The solid substance under examination is either pure metal or an alloy.