), a plumb-line,
string with a piece of metal attached, used by masons, carpenters,
&c. to test the correctness of their perpendicular lines (Vitr. 7.3
19.18): hence the expression ad
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
line for measuring horizontally. This linea
called in Greek also (σχοῖνος
and, from its being coloured to make a
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.
: 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,
= ad perpendiculum.