. A treatise on pharmacy .. . tion of paper filters is an extremely simple thing whenonce learned, and is easily taught the student by a practical demon-stration ; it is, nevertheless, a difficult thing to describe clearly with-out giving to it more space than may appear at first sight due to sosmall a matter. There are two kinds of paper filters, the plain and the plaited; thelatter of which is to be preferred, the chief advantage of the plain FOLDING FILTERS. 107 filter being where we desire to collect the solid ingredient presentin the liquid, and to remove it afterwards from the paper; owi
. A treatise on pharmacy .. . tion of paper filters is an extremely simple thing whenonce learned, and is easily taught the student by a practical demon-stration ; it is, nevertheless, a difficult thing to describe clearly with-out giving to it more space than may appear at first sight due to sosmall a matter. There are two kinds of paper filters, the plain and the plaited; thelatter of which is to be preferred, the chief advantage of the plain FOLDING FILTERS. 107 filter being where we desire to collect the solid ingredient presentin the liquid, and to remove it afterwards from the paper; owingto its being so readily folded, it is in very common use. The method of folding the plain filter is similar to the first stepsto be taken in folding the plaited filter. In the following descriptionI have endeavored to convey an idea of this process. A square piece of filtering paper, abed (Fig. 97), is folded overin the middle, so as to form a crease at the line ef; the edge c d being Fig. 98. Fig. 97. <« 1 6 1 1j \c J,. laid directly over a b. The parallelogram, a b ef, represents thepaper thus folded ; the line b f being now laid upon the line a e, acrease is formed as represented by the line g h (Fig. 98); the foldedpaper, if opened, makes a cone, having the pointh at its base, and by cutting off the projectingangle a, by a curved line from e to g, a plainfilter will be the result, as shown in Fig. 99. The plaited filter is made as follows: Take thepaper before being cut, as above, and havingopened it again so as to expose the parallelogram,the line e h (Fig. 100) is laid upon the line c h,forming a crease at a h. This being openedagain the line e h is laid upon the line a h, pro-ducing an additional crease at g h (Fig. 101).
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Keywords: ., bookcentury1800, bookdecade1860, booksubjectpharmacy, bookyear186
