. The silver sunbeam : a practical and theoretical text-book on sun drawing and photographic printing. to allow water topass through readily. Paper is the substance most gener-ally used for this purpose. The paper best adapted for the filtration of the bulkyand heavy gold and sil-ver precipitates, is thatknown as German filter-ing paper, which, besidesbeing very strong in tex-ture, allows the water torun through very a precipitate is ofa bulky nature, and, es-pecially if accompaniedby much water, a plaitedfilter should be made use of, as it prevents a close adhesionof the paper to
. The silver sunbeam : a practical and theoretical text-book on sun drawing and photographic printing. to allow water topass through readily. Paper is the substance most gener-ally used for this purpose. The paper best adapted for the filtration of the bulkyand heavy gold and sil-ver precipitates, is thatknown as German filter-ing paper, which, besidesbeing very strong in tex-ture, allows the water torun through very a precipitate is ofa bulky nature, and, es-pecially if accompaniedby much water, a plaitedfilter should be made use of, as it prevents a close adhesionof the paper to the glass, thereby greatly expediting theprocess. To form a plaited filter, take a square of good porouspaper and fold it diagonally, as in Figure 6. Turn A uponB to obtain the crease E, and open it; then double A uponE in the same direction to make crease G; and holdingthis plait between the fingers, make the fold between P andD divide the space between E B and B D in the samemanner. Figure 7 shows the position of the filter in the the filter has been properly secured in the funnel,. REDUCTION OF WASTE RESIDUES. 441 and previous to the addition of a liquid containing a pre-cipitate, the filter should be thoroughly wet with some cleanwater, as by these means the pores of the paper are opened,rendering the filter less liable to clog than if the turbidliquid were added immediately. There are, however, someprecipitates, like the chloride and sulphide of silver, which,so completely clog certain kinds of paper, as to prevent theslightest passage of water. In such cases a bag of felt mustbe made use of. A very convenient filter for chloride of silver, when largequantities are operated upon, is an old felt hat, suspendedfrom four corners by means of strings, which should befastened to the ceiling above the ^ sink. When paper is used for fil-tering liquids which passthrough very slowly, a series ofsmall funnels with plaited filtersshould be made use of. Largefunnels are o
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