44 PRACTICAL ORGANIC CHEMISTRY a double neck (Fig. 22(G)) of the Claisen type, for a capillary inlet-tube and a thermometer; steam-splash heads, such as Fig. 22(H) and Fig. 22(1), the latter having an additional inlet-tube for steam-distillation: adaptors having two or three necks (Fig. 22(J)). Similar flat-bottomed flasks and conical flasks are used when more convenient. The above units can when required be fitted into the neck of a flask by adaptors such as Fig. 22(K) and Fig. 22(L). The distillation heads Fig. 22(F) and Fig. 22(G) can be fitted with thermometers having a ground-glass cone just above the bulb (Fig. 22(M)). These are expensive, and it is usually more convenient to fit a thermometer pocket (Fig. 22(N)) which consists of a small "well", fitting as shown into the neck of the flask. A small volume of mercury is placed in the well just to cover the bulb of a conventional thermometer, and thus provides excellent thermal contact between the thermometer and the sides of the pocket. Capillary tubes for low-pressure distillations are prepared by drawing out
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.