ASTRAG´ALUS
ASTRAG´ALUS (
ἀστράγαλος) literally signifies that particular bone in the
ankles of certain quadrupeds which the Greeks, as well as the Romans, used
for dice and other purposes, as described under the corresponding Latin word
TALUS
As a Latin word,
astragalus is used by
Vitruvius, who of course borrowed it from the Greek writers on architecture,
for a certain moulding (the astragal), which seems to have derived its name
from its resemblance to a string or chain of
tali; and it is in fact always used in positions where it seems
intended to bind together the parts to which it is applied. It belongs
properly to the more highly decorated forms of the Ionic order, in which it
appears as a lower edging to the larger mouldings, especially the
echinus (ovolo). particularly in the capital, as
shown in the following woodcut, which represents an
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Astragalus, from Ionic capital.
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Ionic capital found in the ruins of the temple of Dionysus at Teos. Still
finer examples occur in the capitals of the temple of Erechtheus or Athene
Polias, at Athens, where it is seen, too, on the sides of the volutes. It is
also often used in the entablature as an edging to the divisions of the
cornice, frieze, and architrave. The lower figure in the woodcut represents
a portion of the astragal which runs beneath the crowning moulding of the
architrave of the temple of Erechtheus. It is taken from a fragment in the
British Museum, and is drawn of the same size as the original.
The term is also applied to a plain convex moulding of the same sectional
outline as the former, but without the division into links, just like a
torus on a small scale: in this form it is.
used in the Ionic base [
SPIRA].
In the orders subsequent to the Ionic,--the Corinthian, Roman Doric, and
Composite,--the astragal was very freely used. The rules for the use of the
moulding are given by Vitruvius (
3.5.3; iv. G.
§ § 2, 3 : Schneid.). Numerous fine examples of it will be
found in the plates of Mauch (
Die Griechischen und Römischen
Bau-Ordnungen, Potsdam, 1845).
[
P.S]
