TRAPE´TUM
TRAPE´TUM a machine for performing the first process
in oil-making, that of crushing the olives (
θλᾶν,
ἀλεῖν,
frangere, molere), so as to separate the pulp
from the stone. This was done in early times merely by treading, and it
seems to us that the “canalis et
solea” of Col. 12.52, 6, which Blümner dismisses
as unintelligible, simply refers to treading olives by a wooden shoe (cf.
SCULPONEA), with a pipe or trough to carry
away the juice. To this succeeded the
mola
olearia and the
trapetum. The former
is preferred by Columella, as being more easily adjusted according to the
size of the berries, so as to avoid breaking the kernel (Col. 12.51): it
appears to have been the same in principle as the corn-mill [
MOLA], formed of two stones,
capable of adjustment, as is described in that article (see also Blumner,
Technol. 1.331). This appears in the relief from Arles
(fig. 1), where two genii are turning round the crushing stone. The
distinction from the cornmill
 |
|
Mola olearia, from a relief at Arles.
|
is that the stones are in inverse order; instead of the lower
fixed stone being conical and the upper revolving stone hollowed (see cut
under
MOLA), the fixed lower stone
is cupshaped, and the revolving stone is conical. The upright cross-handled
beam is both a pivot for the revolving stone and a means of adjusting the
pressure by raising it or lowering it.
The form of the trapetum, properly so called, can be ascertained from the
remains found at Pompeii and Stabiae. In the cut below, the press found at
Stabiae is shown in elevation and section (from Blümner, after
Schneider).
[p. 2.868]
The berries were placed in a circular stone basin (
mortarium, 1), of which the sides were called
labra: in the centre of this basin stood a
 |
|
Trapetum in elevation and section.
|
column (
miliarium, 2) to support the
poles or levers (
modioli, 6), on which the
crushing stones (
orbes, 3) rested, and by which
they were turned round. These
orbes were of
stone, flat on the inner side and convex on the outer, as if forming two
halves of a sphere: they were kept apart by a rectangular box of wood plated
with metal, and called
cupa (5), into which the
modioli were fixed, and which served also to support the orbes. This
cupa revolved round an iron pivot (
columella ferrea, 4) fixed on the top of the
miliarium or column, and rested on the
column itself. To prevent it from slipping off the pivot, there was an iron
pin (
fistula ferrea, 7). To keep the orbes in
position as close to the cupa as was required, a cap (
armilla, 8) was fastened by a nail to the poles on the
outside or convex surface of the stones: this cap not only kept the stones
steady, but also to some extent regulated their distance from the labra and
their consequent pressure. Two men (for, as Blümner remarks, we
have no mention of horses or mules for this labour) moved round the poles,
so that the stones bruised the fruit against the sides of the mortar. It
must be observed that these poles are to be regarded not as axles, but as
levers: the
columella or pivot was practically
the axle on which they worked. Moreover, as the stones were not fastened to
the poles, they revolved to some extent on their own axis under the pressure
of the fruit, whence there was a double motion and a more yielding pressure,
the object being as much as possible to avoid crushing the kernels, which
would give an unpleasant taste to the oil.
We have no data for a description of another machine for this purpose which
Columella (12.52) calls a
tudicula: he merely
tells us that it worked “like an upright tribula” (which would
seem to imply the principle of tearing or carding the fruit), and that it
easily got out of order. (Blümner,
Technologie,
1.326-336; Rich, s.v. Schneider, in
Script. R. R.）
[
G.E.M]
