METHODS AND MANIPULATION 13 The filtration of any solution through the ordinary conical funnel may be hastened considerably by the use of a "fluted" filter-paper, instead of one folded into quarters in the usual way. The folding of a fluted paper may be learnt far more readily by a demonstration in the laboratory than by any written description. The following is one of the simplest ways of fluting a filter-paper. First make four folds in the paper so that the latter is divided into eight equal sectors (Fig. 7(A)), the two halves of the paper on each occasion being folded forwards, so that all the folds tend to be concave. Now take each segment in turn (e.g., aOb, Fig. 7(8)) and fold the points a and b backwards until they meet, so that a new convex fold Ox is made between them: continue in this way making new folds Oy, Oz, etc., around the paper. When the complete fluted paper (Fig. 7(0)) is placed in the ordinary conical funnel, it will possess a series of regular corrugations, and only the edges of the folds
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