File:A treatise on pharmacy for students and pharmacists (1895) (14580548269).jpg

Identifier: treatiseonpharma00casp (find matches)
Title: A treatise on pharmacy for students and pharmacists
Year: 1895 (1890s)
Authors: Caspari, Charles, jr. (from old catalog)
Subjects: Pharmacy
Publisher: Philadelphia, Lea brothers & co.
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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ovide for the necessary escape of air from the receivingvessel, whenever a funnel is placed in a bottle a piece of twine or astrip of paper should be placed between the neck of the bottle andthe tube of the funnel, the end of which should invariably projectbelow the neck of the bottle. When a paper filter is placed in a funnel, its upper edges shouldnever quite reach to the rim of the funnel (better one-half inch below),so as to allow the funnel to be covered with glass or sheet-rubber, forthe purpose of keeping out dust and preventing evaporation ; besides,if the filter projects beyond the funnel, considerable liquid will bedrawn to the upper edges, owing to the capillarity of the paper, andevaporated, thus entailing loss. In pouring a liquid into a filter, itshould never be allowed to fall in a stream upon the apex or point,which is likely to break from the sudden force, but should be directedagainst the side by means of a guiding-rod, as shown in Figs. 126and 127. Fig. 126. Fig. l:
Text Appearing After Image:
Manner of pouring liquids into a, filter with the aid of a guiding-rod. To insure a continuous supply of liquid to the filter, a bottle con-taining the fluid may be inverted over the funnel, in the mannershown in Fig. 101, for supplying menstruum to a percolator. For filtration of very volatile liquids, a glass tube, bent as inFig. 128, may be placed under the filter against the side of thefunnel; the twisted end will prevent the tube from slipping down, SEPARATION OF XOX-VOLATILE MATTER. 141 Fig. 128. and air from the receiving-bottle can readily pass up through thetube, which should reach a little above the paper filter. The funnel,which should pass air-tight through a cork, mustalso be closed hermetically at the top. Occasionally the filtration of substances which arenot fluid at ordinary temperature becomes necessary,such as mutton suet, wax, petrolatum, ointments, etc.;this can be effected either by means of a hot-air funnelor a water-bath funnel. When hot air is to be used,the f

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