Fig. 31 (Pat. 355,050--C.A. Backstrom) shows another very late style of
creamer. A pipe delivers the milk into P^{4}. Passing out of the tube
separation takes place, and cream falls down the center to P^{2} and
out of O^{3}. When the compartment under the first shelf becomes full
of the skim milk, the latter passes up through the slot, S, strikes a
radial partition, R, and its course is reversed. Here more cream
separates and passes to center and falls directly, and so on through
the whole series of annular compartments, until the top one, when the
skim milk enters tube T^{2} and passes out of O^{2}. By this operation
there are substantially repeated subjections of specified quantities of
milk to the action of centrifugal force, bringing about a thorough
separation. By changing the course of the milk in direction, its path
is made longer. This machine can run at much lower speed than many
other styles, and yet do the same work.

[Illustration: Fig. 31]

CLASS III., SOLIDS FROM SOLIDS.--As for grain machines, which are in
this class, it may be said that in centrifugal flour bolters, bran
cleaners, and middlings purifiers, though theoretically centrifugal
force plays an important part in their action, yet practically the real
separation is brought about by other agencies: in some by brushes which
rub the finer particles through wire netting as they rotate against it.

The principle exhibited in a separator of grains and seeds is very
neat. (Pat. 167,297.) See Fig. 32. That part of the machine with which
we have to do consists essentially of a horizontal revolving disk. The
mixed grains are cast on this disk, pass to the edge, and are hurled
off at a tangent. Suppose at A. Each particle is immediately acted on