_verbum_, _circus_, _corpus_, _laburnum_, the vowels are a separate
class of long vowels, though not really recognized as such. Of course
our ancestors and the Gradus marked them long because in verse the
vowel with the two consonants makes a long unit.

2. A fully stressed vowel before a mute and _r_, or before _d_
or _pl_, was pronounced long in the penultima. Latin examples are
_labrum_, _Hebrum_, _librum_, _probrum_, _rubrum_, _acrem_, _cedrum_,
_vafrum_, _agrum_, _pigrum_, _aprum_, _veprem_, _patrem_, _citrum_,
_utrum_, _triplus_, _duplex_, _Cyclops_. Moreover, in other syllables
than the penultima the vowel in the same combinations was pronounced
long if the two following vowels had no consonant between them, as
_patria_, _Hadria_, _acrius_. (Our 'triple' comes from _triplum_ and
is a duplicate of '_treble_'. Perhaps the short vowel is due to its
passage through French. Our 'citron' comes from _citronem_, in which
_i_ was short.)

3. The preposition and adverb _post_ was pronounced with a long vowel
both by itself and in composition with verbs, but its adjectives
did not follow suit. Hence we say in English 'p[=o]stpone', but
'p[)o]sterior' and 'p[)o]sthumous'.

Monosyllables ending in a vowel were pronounced long, those ending in
a consonant short. Enclitics like _que_ were no real exception as
they formed part of the preceding word. There were, however, some real
exceptions.

1. Pronouns ending in _-os_, as _hos_, _quos_. These followed _eos_
and _illos_.