. An encyclopædia of gardening; . taste is somewhat acrid; but they are withoutsmell when pure. Their specific gravity varies from IOISO to 1-2289. Theyare non-conductors of electricity, and when excited by friction their electri-city is negative. The species of resins are numerous. CS2. Roain is a species of resin, of wliich there are several varie-ties. — From different species of the pine, larch, and fir-tree,there exudes a juice which concretes in the form of tears. Itsextrication is generally aided by means of incisions, audit re-ceives different appellations, according to the species fro
. An encyclopædia of gardening; . taste is somewhat acrid; but they are withoutsmell when pure. Their specific gravity varies from IOISO to 1-2289. Theyare non-conductors of electricity, and when excited by friction their electri-city is negative. The species of resins are numerous. CS2. Roain is a species of resin, of wliich there are several varie-ties. — From different species of the pine, larch, and fir-tree,there exudes a juice which concretes in the form of tears. Itsextrication is generally aided by means of incisions, audit re-ceives different appellations, according to the species from•which it is obtained. If it is obtained from the pinus syl-vestris, it is denominated common turpentine; from pinus larix,Venice turpentine ; from amyris balsamea, balsam of Canada. Itconsists of two ingredients, oil of turpentine and rosin. Theoil is extricated by distillation, and the rosin remains the distillation is continued to dryness, the residuum iscommon rosin or colophonium; but if water is mixed with it. while yet fluid, and incorporated by violent agitation, the resi-duum is yellow rosin. The yellow rosin is the most ductile,and the most generally used in the arts. 683. Pitch and tor are manufactured from the resinous juices»>f the fir. The trunk is cut or cleft into pieces of a convaiient size, which are piled to-gether in heaps, and co-vered with turf. They arethen set on fire, and theresinous juice which is thusextricated, being prevented from escaping in a volatile state by means of the turf, isprecipitated and collected in a vessel beneath. It is partlv converted into an empyreumatic oil, and is now tar, which, bybeing further inspissated, is converted into is extracted from the pistacia is obtained from the juniperis conimutaneous is extracted from the amyris is the produce of the fagara octandra and Vonuk-sbalsamifera. Labdmiim is obtained from the eistus creticus. by sp
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Keywords: ., bookcentury1800, bookdecade18, booksubjectgardening, bookyear1826
