P. CAZENEUVE publishes in the _Comptes Rendus_ a new method for the
preparation of acetylene, which consists in mixing iodoform intimately
with moist and finely divided silver. An abundant evolution of acetylene
takes place without heating. The reaction is represented by the
following formula: 2CHI_{3} + 6Ag = C_{2}H_{2} + 6 AgI. The
decomposition of the iodoform is hastened if the silver is mixed with
finely divided copper, such as can be obtained by precipitating it from
its sulphate by means of zinc.
Cazeneuve also observed that most metals which have any affinity for
iodine will decompose iodoform in the presence of water, forming
acetylene and an iodide of the metal. By the use of zinc he obtained a
liquid having a pleasant ethereal odor, and a gas mixture that contained
besides acetylene an iodine compound which burned with a purple-edged,
fawn-colored flame.
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