difficulty experienced with belting is in getting up speed
and stopping. The basket must not be started with a sudden impulse. Its
inertia will resist and something must give way. A gradual starting can
be obtained by the slipping of the belt at first, but this is
expensive. The best plan is to conduct the power through a species of
friction clutch--an iron disk between two wooden ones. This has been
found to work admirably.

BRAKES.--The first centrifugals had no brakes. They ran until the
friction of the bearings was sufficient to stop them. This occasioned,
however, rapid wearing and too great a loss of time. The best material
for a brake consists of soft wood into which shoe pegs have been
driven, and which is thoroughly saturated with oil. The wooden disks
referred to just above are of the same construction. The center of
oscillation ought to be in the central plane of the brake as well as
that of the pulley, but the preference is given to the pulley.

Figs. 15 and 16 (I) give sectional views of a brake for hanging
machines. Figs. 19, 20, and 21 give two sections and a view of a brake
which can be used on both hanging and standing machines. A very simple
form of brake is shown in Figs. 24, 26, and 27 (A), a mere block
pressing on the rim of the basket.

OIL AND FAT.--A machine in most respects like a whizzer is used for the
"extraction of oil and fat and oily and fatty matters from woolen yarns
and fabrics, and such other fibrous material or mixtures of materials
as are from their nature affected in color or quality when hydrocarbons
are used for the purpose of extracting such oily or fatty matters, and
are subsequently removed from the material under treatment by the slow
process of admitting steam, or using other means of raising the
temperature to the respective boiling points of such hydrocarbons, and
so driving them off by evaporation." In the centrifugal method
carbon-bisulphide, or some other volatile agent, is admitted and is
driven through the material by centrifugal force, when the necessary
reactions take place, and is allowed to escape in the form of
hydrocarbons. A machine differing only in slight particulars from the
above is used for cleansing wool.

LOOSE FIBER.--Another application is the drying of loose fiber. Two
distinctive points deserve to be noticed in the centrifugal used for
this purpose. An endless chain or belt provided with blades moves the
material vertically in the basket, and disc