will deposit nearer to or at the center, their centrifugal force not
being sufficient to carry them out. A mere rod, extending radially in
both directions, serves by its rotation to set the water in motion.

Another form of filter of this second kind (Pat. 148,513) has a
rotating imperforate basket into which the impure liquor is run. Within
and concentric with it is another cylinder whose walls are of some
filtering medium. The liquid already partly purified by centrifugal
force passes through into the inner cylinder, thus becoming further
purified. Centrifugal filters are used also to cleanse gums for
varnishes.

HONEY.--The simplest form of honey extractor (Pat. 61,216) consists of
a square framework, symmetrical with respect to a vertical spindle.
This framework is surrounded by a wire gauze. The combs, after having
the heads of the cells cut off, are placed in comb-holders against the
wire netting on the four sides, the cells pointing outward. The machine
is turned by hand. The honey is hurled against the walls of a receiving
case and caught below. But few improvements have been made on this. The
latest machines are still hand-driven, as a sufficiently high velocity
can be obtained in this manner. In one style the combs are placed upon
a floor which rests upon springs. The rotating box is given a slight
vertical and horizontal reciprocatory motion, by which the combs are
made to grate on the wire gauze sides, breaking the cells and
liberating the honey. Thus the labor of cutting the cells is saved.
Every comb has two sides, and to present each side in succession to the
outside without removing from the basket, several devices have been
patented. In some the comb holders are hinged in the corners of the
basket, and have an angular motion of ninety degrees. Decreasing the
speed is sufficient to swing these. The other side is then emptied by