In Hanbury and
Fluckiger's Pharmacographia there is a full description of the manner
in which the trees are wounded to obtain the turpentine. Besides these
there are Venice turpentine from the larch, _Pinus Larix_, Strassburg
turpentine from _Abies pectinata_, and Canada balsam from _Pinus
balsamea_.
The crude American turpentine is a viscid liquid of about the
consistence of honey, but varying to a soft solid, known as gum, thus,
according to the amount of exposure which it has undergone, it
contains about 10 to 25 per cent. of "spirits," to which the name of
turpentine is commonly given, the rest being resin, or as it is
usually called, rosin.
In Liverpool almost all the spirits of turpentine comes from America,
so that it is almost impossible to get a sample of French.
The terpene from American turpentine is called austraterebenthene. It
possesses dextro-rotatory polarization of +21.5. Its density is 0.864.
Boiling point 156 deg. C.
In taking the boiling point of a commercial sample of spirits it is
necessary to wait until the thermometer becomes steady. Not more than
5 per cent. should pass over before this takes place, and then there
is not more than two or three degrees of rise until almost all is
distilled over.
The liquids of lower boiling point do not appear to have been much
studied. In French spirits they seem to be of the same composition as
the main product, but with more action on polarized light.
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