PINUS SYLVESTRIS. 
17 
soft resinous crust, called by the French harras, when impure and 
mixed with dust, sand, &c.; and gallipot when collected with more 
care ; this is scraped otF and is used in the making of flambeaux, 
but the greater part of it is purified and converted into yellow resin. 
All these different products pf the Pinus Sylvestris are purified by 
liquefaction and filtration; they consist almost entirely of essential - 
oil and resin, dilfering only in the proportions^ the turpentine con- 
taining the largest proportion of oil, and the gallipot of resin ; 
indeed the quantity of essential oil in the latter is so small that it is 
never subjected to distillation ; it is purified by melting it over a 
gentle fire and filtrating; in this form it is often sold for Burgundy 
pitch, as is likewise a simple mixture of gallipot and barras made 
without heat ; but the mass resulting from this combination soon 
becomes friable, and has neither the unctuosity, viscidity, tenacity, 
nor smell, which distinguish the real kind. If boiling water be 
added to the melted gallipot after it is strained, but while yet fluid, 
and the two agitated together, a yellow resin is obtained, which, 
fi-om still containing some essential oil, is preferred to the resin 
prepared by a similar process from the residuum after the distillation 
©f turpentine. 
Sensible and Chemical Properties of Common Tur- 
■"PENTINE AND THE Resins. The juice of pines in general has 
an austere, astringent, warm and pungent taste, great viscosity, is 
more or less fluid according to the species, with diff'erent degrees of. 
transparency, and is of a whitish or yellowish colour, with a pene- 
trating smell. It is entirely soluble in alcohol, combines with fixed 
oils, and imparts its flavour to water but is not soluble in it 3 by a 
moderate heat it is decomposed, yielding a highly penetrating 
essential oil, of which we shall hereafter speak, and leaving the 
liquor impregnated with an acid, the succinic ; a bitter resinous 
substance remaining behind. Turpentine therefore consists of an 
essential oil, resin^ and succinic acid, and the purest turpentine is 
that which yields the largest quantity of the first of these substances ; 
turpentine is exceedingly inflammable, burning with a large white 
flame and much smoke. Common turpentine is more coarse and 
dense than the other kinds, it is about the consistence of honey, and 
of a light brown or dirty yellow colour, its taste is very acrid, hot 
and natiseous. and smell more penetrating and disagreeable than the 
purer turpentines; for this reason the use of it is chiefly confined to 
• farriers for their plasters and ointments. It is likewise extensively 
used for the distillation of the essential oil. According to modern 
chemistry the resins stand in the same relation to the volatile oil*. 
VOL. II. ^ 
