The other figures relate to details that will be referred to further
along.

_The Decorticating Cylinder._--The principal part of the apparatus is
a hollow drum, A, of cast iron, 430 mm. in internal diameter by 1.41
m. in length, which is keyed at its two extremities to the shaft, a.
Externally, this drum (which is represented apart in transverse
section in Fig. 5) has the form of an octagonal prism with well
dressed projections between which are fixed the eight plates, C, that
constitute the decorticating cylinder. These plates, which are of
tempered cast iron, and one of which is shown in transverse section in
Fig. 7, when once in place form a cylindrical surface provided with 48
helicoidal, dentate channels. The length of these plates is 470 mm.
There are three of them in the direction of the generatrices of the
cylinder, and this makes a total of 24. All are strengthened by ribs
(as shown in Fig. 8), and each is fixed by 4 bolts, _c_, 20mm. in
diameter. The pitch of the helices of each tooth is very elongated,
and reaches about 7.52 m. The depth of the toothing is 18 mm.

_Frame and Endless Chain._--The cylinder thus constructed rotates with
a velocity of 50 revolutions per minute over a cylindrical vessel, B',
cast in a piece with the frame, B. This vessel is lined with two
series of tempered cast iron plates, D and D', called exit and
entrance plates, which rest thereon, through the intermedium of well
dressed pedicels, and which are held in place by six 20-millimeter
bolts. Their length is 708 mm. The entrance plates, D, are provided
with 6 spiral channels, whose pitch is equal to that of the channels
of the decorticating cylinder, C, and in the same direction. The depth
of the toothing is 10 mm.