PERPENDI´CULUM
PERPENDI´CULUM (
κάθετος,
μολυβδίς,
στάθμη),
a plumb-line, a
string with a piece of metal attached, used by masons, carpenters,
&c. to test the correctness of their perpendicular lines (
Vitr. 7.3,
5; Isid.
Or. 19.18): hence the expression
ad
perpendiculum of the correct line (
Cic. Ver. 1.51, 133;
Caes. Gal. 4.17, &c.). Cicero
(
ad Qu. Fr. 3.1, 2) distinguishes it from
linea (=
κανών), the
line for measuring horizontally. This
linea was
called in Greek also (
σχοῖνος and
σπαρτίον, and, from its being coloured to make a
mark,
μιλτεῖον. Blümner, wrongly
we think, excludes
στάθμη from this sense,
and makes it altogether equivalent to
perpendiculum. There is no doubt that
[p. 2.374]it was sometimes a plumb-line, as in
Anth. Pal. 6.103,
(
στάθμην μολιβαχθέα: but that it was
also (perhaps more commonly) a horizontal line is clear from its use to make
a straight
τάφρος in
Hom. Od. 21.121. It was probably a line
getting the true direction either way; and the expressions
παρὰ στάθμην, ἐπὶ στάθμην would come from
either use. We have also the phrases
πρὸς κάθετον,
εἰς κάθετον =
ad perpendiculum.
(Blümner,
Technologie, 2.235.)
[
G.E.M]
