ine becoming
slightly colored upon further evaporation. It possesses also still a
slight smell and taste of lead plaster, which may be removed by diluting
it with water, and by digestion with animal charcoal, and some fresh
burnt-wood charcoal. After filtration, this liquid must be evaporated
until it has acquired a specific gravity of 1.21, when it will be found
to be free from smell, and of a pale yellow color. For the preparation
of glycerine, distilled water is necessary, to prevent it being
contaminated with the impurities of common water. Jahn obtained, by this
method, from the above quantity of lead plaster, upwards of seven ounces
of glycerine.--_Archives der Pharmacie_.

* * * * *

TEST FOR ALCOHOL IN ESSENTIAL OILS.

J.J. Bernoulli recommends for this purpose acetate of potash. When to an
ethereal oil, contaminated with alcohol, dry acetate of potash is added,
this salt dissolves in the alcohol, and forms a solution from which the
volatile oil separates. If the oil be free from alcohol, this salt
remains dry therein.

Wittstein, who speaks highly of this test, has suggested the following
method of applying it as the best:--In a dry test-tube, about half an
inch in diameter, and five or six inches long, put no more than eight
grains of powdered dry acetate of potash; then fill the tube two-thirds
full with the essential oil to be examined. The contents of the tube
must be well stirred with a glass rod, taking care not to allow the salt
to rise above the oil; afterwards set aside for a short time. If the
salt be found at the bottom of the tube dry, it is evident that the oil
contains no spirit. Oftentimes, instead of the dry salt, beneath the oil
is found a clear syrupy fluid, which is a solution of the salt in the
spirit, with which the oil was mixed. When the oil contains only a
little spirit, a small portion of the solid salt will be found under the
syrupy solution. Many essential oils frequently contain a trace of
water, which does not materially interfere with this test, because,
although the acetate of potash becomes moist thereby, it still retains
its pulverent form.

A still more certain result may be obtained by distillation in a
water-bath. All the essential oils which have a higher boiling-point
than spirit, remain in the retort, whilst the spirit passes into the
receiver with only a trace of the oil, where the alcohol may be
recognized by the smell and taste. Sh