PAPER TO BE USED.
A perfectly pure paper is not quite so essential as in the process previously described, the chief consideration being that it is of a good colour and sufficiently opaque ; that is to say, when laid over a sheet of newspaper, the reading matter must not show through. Provided the paper fulfils these conditions, its thick ness is of no consequence. Suitable papers may be obtained in small quan tities from the dealers—the usual size is 2 in. by 11 in. ; but if the size referred to is reduced to a perfectly limpid state. Having allowed it to settle. place a small sponge in the neck of the glass funnel and let the solution filter slowly through. The solution must be free from bubbles, so that the funnel should touch the side of the vessel into which it filters, the fluid 'mining down the side. The method known as upward filtration has also been recommended, and certainly has its ad vantages. Take an ordinary glass jam jar, and trace a line round it about .1 in.
from the bottom with a red-hot poker ; this should cause the glass to crack, and it smartly done the crack will follow the direction of the poker, when all that is necessary further is to hit the jar a sharp LI w, and the bottom will drop out, leaving the bottomless jar with a ring round its edge, as shown in Fig. 255. Over this is tied two thicknesses of washed muslin C. The albumen is placed in a vessel B just large enough to admit the upward filter. The filter has now to be placed muslin end downwards in the liquid, when the weight of the jar forces the solution through the muslin. One ounce of this cannot be procured, any convenient di mensions may be taken, using the propor tionate quantity of albumen. Hives and Saxe papers are the best for this purpose, but are not readily obtainable uncoated. Rives is a thin paper, and Saxe a heavy paper suitable for larger sizes ; the bank post papers are also suitable.