. Elementary chemical microscopy . Fig. 154. edges selected to fit edge to edge may be clamped together. In certain instances either one of these watch glass methods may prove to be more practicable than the crucible. In all cases, however, the clamp support is far superior to the fingers. Although the device just described may be satisfactorily applied to the fractional distillation of small amounts of volatile liquids, small distilling tubes will be found in certain cases to be somewhat safer for very volatile substances. These are readily made from small glass tubing of thin wall as shown i
. Elementary chemical microscopy . Fig. 154. edges selected to fit edge to edge may be clamped together. In certain instances either one of these watch glass methods may prove to be more practicable than the crucible. In all cases, however, the clamp support is far superior to the fingers. Although the device just described may be satisfactorily applied to the fractional distillation of small amounts of volatile liquids, small distilling tubes will be found in certain cases to be somewhat safer for very volatile substances. These are readily made from small glass tubing of thin wall as shown in Fig. 155. The finished distilling tube is shown in A. To introduce the liquid to be distilled a rubber pipette cap r is slipped over the large end of the tube (Fig. 155 B); the tube is inverted as shown, the drawn-out end of the tube is dipped into the liquid to be distilled and the rubber bulb is compressed just enough so that when released the liquid will rise into the bulb in sufficient volume to not quite half fill it. The tube is then again turned to the position A, the bulb surrounded by ice and the drawn-out tube sealed off in the flame of a blast lamp or blow pipe. The bulb is removed from the ice, wiped dry and the apparatus arranged as shown in Fig. 155 C. The liquid may now be heated
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectmicroscopy, bookyear1
