A System of Instruction in the Practical Use of the Blowpipe: Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic CombinationsAnonymous
Science
A System of Instruction in the Practical Use of the Blowpipe: Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations
Anonymous
Blowpipe
Microcosmic salt dissolves the compounds of antimony in the flame of
oxidation with intumescence, to a clear light-yellow colored bead,
which when cold is colorless. Heated upon charcoal in the reduction
flame, the bead is first turbid, but soon becomes transparent. The
addition of tin renders the bead greyish while cooling, but a
continued blast renders it transparent. Soda dissolves the compounds
of antimony upon platinum wire in the oxidation flame, to a clear
colorless bead, which is white when cold.
Upon charcoal, both in the oxidation and reduction flames, the
antimony compounds are readily reduced to the metal, which is
immediately volatilized, and produces a white incrustation of oxide of
antimony upon the charcoal. If the antimony compounds are heated upon
charcoal in the flame of reduction, with a mixture of carbonate of
soda and cyanide of potassium (KCy), there are produced small globules
of metallic antimony. At the same time, a part of the reduced metal is
volatilized (this continues after the assay is removed from the flame)
and re-oxidized. A white incrustation appears upon the charcoal, and
the metallic globules are covered with small white crystals. If this
white sublimate upon the charcoal is moistened with a solution of
cobalt-oxide, and exposed to the reduction flame, a part of it is
volatilized, while the other part passes into higher oxidation, and
remains, after cooling, of a dirty dark-green color.
(_d._) _Tellurium_ (Te).--This is one of the rare metals. It occurs
very seldom in the metallic state, but often with bismuth, lead,
silver, and gold. Tellurium, in the pure state, is silver-white, very
bright, of a foliated or lamellar structure, brittle, and easily
triturated. It is inclined to crystallize. It is soluble in
concentrated sulphuric acid without oxidation. The solution is of a
fine purple color, and gives a precipitate with the addition of water.
_Tellurium in the Metallic form._--By the aid of heat it is oxidized
in sulphuric acid, a portion of the oxygen of the acid oxidizing the
metal, while sulphurous acid gas escapes. This solution is colorless,
and is tellurous acid, dissolved in sulphuric acid. It melts at a low
red heat, and volatilizes at a higher temperature. If tellurium is
heated with free access of air, it takes fire, and burns with a blue
color, the flame being greenish at the edges, while a thick white
vapor escapes, which has a feeble acidulous odor.
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