), which properly means a snail, was also
used to signify other things of a spiral form. [p. 1.464]
1. A screw. The woodcut annexed represents a clothes-press, from a painting
on the wall of
Clothes-press worked by two upright screws. (|
at Pompeii, which is
worked by two upright screws (cocleae
precisely in the same manner as our own linen presses.
A screw of the same description was also used in oil and wine presses. (Vitr. 6.9
4.10.10, 2.19.1.) The thread of the screw, for which the Latin language has
no appropriate term, is called περικόχλιον
in Greek. (Schneid. Ecl. Phys.
2. A spiral pump for raising water, invented by Archimedes (Diod. 1.34
Strab. xvii. pp. 807, 819; Athen. 5.208
whom it has ever since been called the Archimedean screw. It is described at
length by Vitruvius (10.11
). It consists of a
pipe coiled like a screw round a long cylinder, which is placed obliquely
with one end in water, and made to revolve on its axis. The water then
gradually rises through the spirals of the pipe. It was much used in Egypt
for irrigation, as it will only raise water to a moderate height.
Coclea, or turnstile. (Medal, British Museum.)
3. Varro refers in the following terms to a coclea
used in the circus :--In giving directions for the
construction of an aviary, he says (R. R.
“ostium habere humile et angustum et potissimum eius generis quod
cocleam appellant, ut solet esse in cavea, in qua tauri pugnare
solent.” Various conjectures have been given as to the meaning of
this passage, but the contorniate medal figured here from the collection in
the British Museum presents the most probable explanation. It shows a
pursued by a bear and taking
refuge behind a sort of turnstile, consisting of four partitions revolving
round an upright post as an axis. (Cf. Gori, Thes. diptych.
i. pll. vii. and xii., with Cassiod. Var.
5.42, where he
speaks of the marvellous way in which the bestiarii
escaped, “in patenti area cancellosis se postibus
occulentes.” ) Thus what Varro recommends is probably a turnstile
fitted into a low doorway.
a spiral staircase (Strab. xvii. p.795