1prone to motion as it revolves.
And so, when the workman turns the axle
by the crank, the fans, the description of which I will give a little later, draw
in the air by the blow-hole, and force it through the other blow-hole which
leads to the conduit, and through this conduit the air penetrates into the
shaft.
by the crank, the fans, the description of which I will give a little later, draw
in the air by the blow-hole, and force it through the other blow-hole which
leads to the conduit, and through this conduit the air penetrates into the
shaft.
The one with the box-shaped casing is furnished with just the same
things as the drum, but the drum is far superior to the box: for the fans so
fill the drum that they almost touch it on every side, and drive into the
conduit all the air that has been accumulated; but they cannot thus fill
the box-shaped casing, on account of its angles, into which the air partly
retreats; therefore it cannot be as useful as the drum. The kind with a
box-shaped casing is not only placed on the ground, but is also set up on timbers
like a windmill, and its axle, in place of a crank, has four sails outside,
like the sails of a windmill. When these are struck by the wind they turn
the axle, and in this way its fans—which are placed within the casing—drive
118[Figure 118]
things as the drum, but the drum is far superior to the box: for the fans so
fill the drum that they almost touch it on every side, and drive into the
conduit all the air that has been accumulated; but they cannot thus fill
the box-shaped casing, on account of its angles, into which the air partly
retreats; therefore it cannot be as useful as the drum. The kind with a
box-shaped casing is not only placed on the ground, but is also set up on timbers
like a windmill, and its axle, in place of a crank, has four sails outside,
like the sails of a windmill. When these are struck by the wind they turn
the axle, and in this way its fans—which are placed within the casing—drive
A—BOX-SHAPED CASING PLACED ON THE GROUND. B—ITS BLOW-HOLE.
C—ITS AXLE
WITH FANS. D—CRANK OF THE AXLE. E—RODS OF SAME. F—CASING SET ON TIMBERS.
G—SAILS WHICH THE AXLE HAS OUTSIDE THE CASING.
WITH FANS. D—CRANK OF THE AXLE. E—RODS OF SAME. F—CASING SET ON TIMBERS.
G—SAILS WHICH THE AXLE HAS OUTSIDE THE CASING.