. The Pharmaceutical era. each of the original fractions toone or more new distillations, there is obtained at lengtha set of liquids having definite boiling points, and there-fore practically pure. Vacuum distillation is where the condenser Is connectedwith an apparatus for reducing the internal pressure,whereby the liquid is caused to boil at a lower tem-perature. It is practically the same as the vacuum evap-oration already described, and accomplished by the samemechanical means, being known as distillation when thevolatile products are condensed and collected, and asevaporation when they a
. The Pharmaceutical era. each of the original fractions toone or more new distillations, there is obtained at lengtha set of liquids having definite boiling points, and there-fore practically pure. Vacuum distillation is where the condenser Is connectedwith an apparatus for reducing the internal pressure,whereby the liquid is caused to boil at a lower tem-perature. It is practically the same as the vacuum evap-oration already described, and accomplished by the samemechanical means, being known as distillation when thevolatile products are condensed and collected, and asevaporation when they are allowed to ;t Still and simplest form of distilla-tory apparatus used in pharmacy Is the retort and re-ceiver (Fig. 54), a lineal descendant of the alembic of theold alchemists. The form of the retort is sufficiently shown by the il-lustration, consisting essentially of a round bottomedflask with a long, tapering neck bent at an acute anglewith the body. Retorts and receivers may be either. Fig. 55.—^Flask Still and Lteblg Condenser. The greatest defect of the retort Is the imperfection ofits condensing power, especially where very voiatileliquids are dealt with, in which cases, or where largequantities of liquid are to be distilled, some of the suc-ceeding forms of still may be preferable. Flask Still with Liebig Condenser —In this form of appara-tus the body cf the retort Is replaced by an ordinarychemical flask of thin glass, and the neck of the retort bya condenser of simple construction, known as Llebigscondenser. (Fig. 55.) The advantages of this apparatusare Its simplicity of construction, the readiness withwhich the flask may be replaced when broken, and theexcellence of its condensing power. In its simplest form the Liebig condenser consists of anarrow tube connected at one end with the distilling flaskand at the other with the receiver, and surrounded bya tube of larger caliber through which the cold water em-ployed for condensing i
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Keywords: ., bookcentury1800, booksubjectdrugs, booksubjectpharmacy, bookyear1
