erwards be suffered to stand quiet, till
the flour is entirely settled, and the water above become perfectly
clear; but if the water has any sensible colour or taste, the flour must
be washed again with fresh water, for it is absolutely necessary that
none of the extractive matter be suffered to remain with it. The flour,
when thus obtained pure, and drained from the water, may be taken out of
the tub with a wooden shovel, and placed upon wicker-frames covered with
paper, to be dried in some situation properly defended from dust. When
the manufacture of starch from potatoes is attempted in a large way,
some kind of mill must be used to reduce them to a pulp, as the grating
of them by hand is too tedious an operation. A mill invented by M. Baume
is very complete for this purpose. In its general structure it resembles
a large coffee-mill: the grater consists of a cone of iron plate, about
seven inches in diameter, and eight inches in height, the exterior
surface of which is made toothed, like a rasp, by piercing holes through
the plate from the inside. This cone is fixed upon a verticle axle, with
a handle at the top to turn it by; and is mounted on the pivots of the
axle, within a hollow cylinder of plate-iron, toothed withinside like
the outside of the cone; the smallest end of the interior cone being
uppermost, and the lower or larger end being as large as the interior
diameter of the hollow cylinder. A conical hopper is fixed to the hollow
cylinder, round the top of it, into which the potatoes are thrown; and
falling down into the space between the outside of the cone and the
inside of the hollow cylinder, they are ground, and reduced to a pulp,
when the interior cone is turned round by its handle; and as the lower
part of the cone is fitted close to the interior diameter of the
cylinder, the potatoes must be ground to a fine pulp before they can
pass through between the two. The machine, when at work, is placed in a
tub filled with water; and as fast as the grinding proceeds, the pulp
mixes regularly with the water, ready for the process before described.
Poland starch is reckoned the best: its quality may be judged of by the
fineness of the grain, its being very brittle, and of a good colour. The
price of starch depends upon that of flour; and when bread is cheap,
starch may be bought to advantage. If it be of good quality it will keep
for some years, covered close, and laid up in a dry warm room. In the
year 1796, lo