The farmer and mechanic. [volume] (Raleigh, N.C.) 1877-1885, 1878-08-15

exposed to the sun and sheltered
from the winds. The former IS
important because when the sumac
is warn and dry the labor Of thresh-
ing is greatly diminished and the
latter is so because the valuable
part of the product Is light and
easily blown away.
No precaution should be omitted
for protecting the crop against the
damage Of rain at the threshing
floor.
GRINDING.
Before the sumac is ground the
leaflets, which contain all the tan
min, are separated from the stems,
which are worthless. This
ton is accomplished by means of
a machine resembling somewhat an
ordinary wheat fan, or winnowing
Mill. Instead, however, Of the
hopper and wire selves of the wheat
fan, there is a large hollow cylin-
der, OF construction similar to that
of the machine in common use for
boiling flour, which rcyolyes, and
is adjusted with the end at which
the sumac enters a little higher
than the other. This cylinder
consists of Il frame work of wood
covered with sheet iron. The iron
is pierced with holes large enough
to let the leaflets fall through,
whilst the stems are conveyed to
the lower end of the cylinder and
discharged. The leaflets fall upon
Il current of air set in motion by
the fan, and are borne off to them
selves us the chaff from wheat. The
pebbles and earth fall through the
current and pass in the direction
of the grain III Il wheat fan.
The leaflets are now ready to be
ground. The accompanying figures
A. b. and c., giving different
views of Il mill Of the most
approved kind, afford an exact idea
of it, and in the hands of a ma
chinist will furnish ample guidance
for It's construction. The stones.
it will be seen, are vertical and
have no easement about them. By
this arrangement We avoid the beat
ing of the sumac which, III mills of
other construction, so much impalrS
its quality.
The process of grinding by this
mill is much more tedious than by
hat in which the stones are horl-
zontal as in Il flour mill, its average
work being about one hundred
pounds of fine ground M per
hour. But in the horizontal mill
the sumac becomes as much heated
that it loses a large proportion of
its fannie strength ; and, in this
account, it has been entirely sup
planted by the vertical.
When the sumac is we'll ground
the mill is stopped by means of the
handle e. f. Gig Al, which throws
it out of gear, and the m is
taken off to make room for a new
supply. 1t is then passed through
a machine similar to that in which
flour is bolted. The object of this
operation is to separate the thor
oughly powdered portion from the
small pieces of the nerves of the
leaflets and the bits of stems,
which, being tougher than the web
of the leaf, have not been triturated
by the stones.
The fine ground sumac is then
put in bags and is ready for use.
The nerves and bits of stems are
subjected to another grinding, but
this time by horizontal burrs, (of
which, for this purpose, every well
equipped establishment should have
one pair) as their toughness rem
ders their trituration by vertical
mill very difficult. The product
thus obtained will be of inferior
quality on account of both the ad-
mixture of the bits of stems which
contain no tannin, and the heat