LĪBRA, _dim._ LĪBELLA σταθμός, a balance, a pair of scales. The
principal parts of this instrument were, 1. The beam (_jugum_). 2.
The two scales, called in Greek τάλαντα, and in Latin _lances_.
The beam was made without a tongue, being held by a ring or other
appendage (_ligula_, ῥῦμα) fixed in the centre.
LĪBRA or AS, a pound, the unit of weight among the Romans and
Italians. The uncial division, which has been noticed in speaking
of the coin As, was also applied to the weight.--(See Tables at the
end.) The divisions of the ounce are given under UNCIA. Where the
word _pondo_, or its abbreviations P. or POND., occur with a simple
number, the weight understood is the _libra_. The name _libra_ was
also given to a measure of horn, divided into twelve equal parts
(_unciae_) by lines marked on it, and used for measuring oil.
LIBRĀRĬI, the name of slaves, who were employed by their masters
in writing or copying, sometimes called _antiquarii_. They must be
distinguished from the Scribae publici, who were freemen [SCRIBAE],
and also from the booksellers [BIBLIOPOLA], to both of whom this name
was also applied.
LĪBRĀTOR, in general a person who examines things by a LIBRA;
but specially applied to two kinds of persons.--(1) _Libratores
aquae_, persons whose knowledge of hydrostatics was indispensable
in the construction of aquaeducts, sewers, and other structures for
the purpose of conveying a fluid from one place to another.--(2)
_Libratores_ in the armies were probably soldiers who attacked the
enemy by hurling with their own hands (_librando_) lances or spears
against them.