A curious method consists in having discharge pipes provided with valves and floats at their lower ends, dipping into the liquid (Pat. 240,175).  “The valves are opened and closed, or partially opened or closed, by the floats attached to them, these floats being so constructed and arranged with reference to their specific gravity and the specific gravity of the component parts of the liquids operated upon, that they will permit only a liquid of a determinate specific gravity to escape through the pipes to which they are respectively attached.”

We may have tubes directed into the different strata with cutting edges. (Pat. 288,782.) A remarkable fact noticed in their use is that these edges wear as rapidly as if solids were cut instead of liquids.

The separated fluids may be received into recessed rings, having discharge pipes, the proportionate quantity discharged being regulated by the proximity of the discharge lips to the surface of the ring, and the centrifugal force being availed of to project the liquids through the discharge pipes.

There is a very simple device by which a very rapid circulation of the liquid is brought about. (Pat. 358,587—­C.A.  Backstrom.) The basket has radial vertical partitions, all but one having communicating holes, alternately in upper and lower corners.  The milk is delivered into the basket on one side of this imperforate partition and must travel the whole circuit of the basket through these communicating holes, until it reaches the partition again, and then passes into a discharge pipe.  Thus during this long course every particle of cream escapes to the center.  As the holes are close to the walls of the basket, the cream has not the undulatory motion of the milk, which would injure it.  The greater the number of partitions, the longer is the travel of the milk, and the more rapid the circulation.  Blades have been devised similar to the above, having communicating passages extending the whole width of the blade, but we see that here the cream would circulate with the milk; which must not be allowed.  Curved blades have been used, and paddles and stirrers, to set the milk in motion, but to them the same objection may be made.

[Illustration:  Fig. 30]

Fig. 30 (Pat. 355,048—­C.A.  Backstrom) illustrates one of the latest and best styles of creamers.  The milk enters at C. The skim milk passes into tube, T, and the cream goes to the center and passes out of the openings in the bottom, k^{l}, k^{2}, and k^{3}, out of the slit, k, and thence out through D^{5}.  The skim milk moves through T, becoming more thoroughly separated all the while, and at each of the radial branch tubes, T^{1}, T^{2}, T^{3}, and T^{4}, some cream leaves it and goes to the center, while it passes down out of slit, t^{3}, and thence out of D^{6}.