QUANTITATIVE ANALYSIS 441 either a number of glass beads or (preferably) some fragments of un-S 'azed porcelain, and adjust the thermometer B in position: the bulb of should be amply covered by the solvent and should just not touch the beads. It is advisable now to wrap some asbestos cord CC 1 loosely in a spiral round the lower portion of T, and then fit T into the jacket J, finally plugging the top of the annular space be-tween T and J loosely with the upper end of the cord: by these means the direct ascent of hot gases in the annular space is prevented, and the tube T cannot come in direct contact with J. Place sufficient solvent in J to bring it approximately level with the top of the beads in T. Adjust the condenser, and then sur-round the whole appar-atus with wind-screens so that it is completely protected from draughts. Now start the heating so that the solvent in both T and J is boiling steadily, and that the con-densed liquid is falling back into T from the condenser at about
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