File:Image from page 34 of "Practical methods of organic chemistry" (1901) (14748611806).jpg

Identifier: practicalmethods00gatt Title: Practical methods of organic chemistry Year: 1901 (1900s) Authors: Gattemann, Ludwig. [from old catalog] Subjects: Publisher: [n.p.] Contributing Library: The Library of Congress Digitizing Sponsor: The Library of Congress

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Text Appearing Before Image: lass withits convex side uppermost is placed on it, andthe two are held together by a watch-glassclamp. If the lower glass is now heated veryslowly on a sand-bath with a free flame, thevaporised substance condenses on the cold sur-face of the upper watch-glass in crystals; thefilter-paper prevents the very small, light crys-tals from falling back on the hot surface of thelower glass. To keep the upper glass cool, it iscovered with several layers of wet filter-paperor with a small piece of wet cloth. If largequantities of a substance are to be sublimed,the upper watch-glass in the apparatus just described is replacedby a funnel somewhat smaller than the lower glass (Fig. 9). Toprevent the escape of vapours, the stem of the funnel is closed bya plug of cotton or is covered with a small cap of filter-paper.The apparatus for sublimation designed by Briihl is admirablyadapted to the purpose for which it is intended (Fig. 10). Itconsists of a hollow metal plate through which water flows. In

Text Appearing After Image: Fig. 9.

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