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A practical treatise on the manufacture of perfumery : $b comprising directions for making all kinds of perfumes, sachet powders, fumigating materials, dentrifices, cosmetics, etc., etc., with a full account of the volatile oils, balsams, resins, and other natural and artificial perfume-substances, including the manufacture of fruit ethers, and tests of their purityDeite, C. (Carl)

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A practical treatise on the manufacture of perfumery : $b comprising directions for making all kinds of perfumes, sachet powders, fumigating materials, dentrifices, cosmetics, etc., etc., with a full account of the volatile oils, balsams, resins, and other natural and artificial perfume-substances, including the manufacture of fruit ethers, and tests of their purity

Name: A practical treatise on the manufacture of perfumery : $b comprising directions for making all kinds of perfumes, sachet powders, fumigating materials, dentrifices, cosmetics, etc., etc., with a full account of the volatile oils, balsams, resins, and other natural and artificial perfume-substances, including the manufacture of fruit ethers, and tests of their purity
Author: Deite, C. (Carl)

Deite, C. (Carl)

Cosmetics; Perfumes; Perfumes industry

II. _Hoppe's nitroprusside of copper test._--This test sometimes gives
good results, but only with hydrocarbons absolutely free from oxygen
and oxygenated oils. It is, therefore, not suitable for oils derived
from the _Aurantiaceæ_. The process is as follows: Add to a small
quantity of the oil to be examined in a perfectly dry test-tube, 2 to
5 milligrammes of pure nitroprusside of copper previously thoroughly
dried and finely pulverized, shake vigorously and gradually heat to
boiling. After boiling for a few seconds allow to cool. If the oil
is free from oil of turpentine, or another oil containing no oxygen,
the precipitate formed is brown, black, or gray, and according to the
quantity of the reagent added and the original color of the oil, the
supernatant oil will be differently colored and appear more or less
dark. If, however, the oil is adulterated with oil of turpentine,
the precipitate formed shows a handsome green or blue-green color,
while the supernatant oil retains its original color or at the utmost
acquires a very slightly darker one. The longer the oil is allowed to
stand after settling, the more distinct and beautiful the color of the
oil and of the precipitate appears. For the establishment and certain
recognition of very small quantities of oil of turpentine in oxygenated
oils, it is best to first add very little of the nitroprusside of
copper to the oil to be tested, and a larger quantity only after being
convinced either of the purity or adulteration of the oil. This is done
to be able, on the one hand, better to judge the reaction, if the oil
is pure, and, on the other, if it is adulterated, to establish such
adulteration with certainty and to approximately estimate the quantity
of oil of turpentine present. The less nitroprusside of copper is used,
the better small quantities of oil of turpentine can be detected.

Nearly all volatile oils free from oxygen show the same behavior
towards nitroprusside of copper; they decompose it, which is not the
case with oxygenated oils. The behavior of the latter is shown in the
following table:--

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