od
is used. So, in the first example, /cum in Gallia eram\ fixes the
time when I saw Caesar.

_b._ On the other hand, when the /cum\ clause _describes the
circumstances_ under which the main act took place, the subjunctive
mood is used. So, in the second example, the principal clause states
that Caesar made an attack, and the /cum\ clause describes the
circumstances under which this act occurred. The idea of _time_ is
also present, but it is subordinate to the idea of _description_.
Sometimes the descriptive clause is one of _cause_ and we translate
/cum\ by _since_; sometimes it denotes _concession_ and /cum\ is
translated _although_.

_396._ RULE. Constructions with _Cum_. _The conjunction /cum\ means
/when\, /since\, or /although\. It is followed by the subjunctive unless
it means /when\ and its clause fixes the time at which the main action
took place._

NOTE. /Cum\ in clauses of description with the subjunctive is much more
common than its use with the indicative.

_397._ Note the following sentences:

1. Oppidum erat parvum magnitudine sed magnum multitudine hominum,
_the town was small in size but great in population_.

2. Homo erat corpore infirmus sed validus animo,
_the man was weak in body but strong in courage_.

_a._ Observe that /magnitudine\, /multitudine\, /corpore\, and
/animo\ tell _in what respect_ something is true. The relation is
one covered by the ablative case, and the construction is called the
_ablative of specification_.

_398._ RULE. Ablative of Specification. _The ablative is used to
denote /in what respect\ something is true._

_399._ IDIOMS

aliquem certiorem facere, _to inform some one_ (lit. _to make some
one more certain_)
certior fieri, _to be informed_ (lit. _to be made more certain_)
iter dare, _to give a right of way, allow to pass_
obsides inter se dare, _to give hostages to each other_

_400._ EXERCISES

I. 1. Helvetii cum patrum nostrorum tempore domo prefecti essent,
consulis exercitum in fugam dederant. 2. Cum Caesar in Galliam venit,
Helvetii alios agros petebant. 3. Caesar cum in citeriore Gallia esset,
tamen de Helvetiorum consiliis certior fiebat. 4. Cum Helvetii bello
clarissimi essent, Caesar iter per provinciam dare recusavit. 5. Legatus
cum haec audivisset, Caesarem certiorem fecit. 6. Cum principes inter se
obsides darent, Romani bellum paraverunt. 7. Caesar, cum id