which have a special meaning and which, being often used in
calendar working, deserve a special note. They are "occurrence" and
"concurrence." _Occurrence_ is the conjunction of two or more offices,
which fall on the same day. It may be accidental when two movable feasts
are concerned or when a movable feast falls on a day which has a fixed
office; or it may be perpetual, when a fixed office falls on a day which
already has a fixed office. The Church does not ask the recitation of a
double or a triple office. She, by her fixed rules, prefers one out of
the two of the "occurring" offices, transfers if possible the others, or
at least commemorates them by an antiphon, versicle and prayer, and
sometimes by a ninth lesson at Matins.

_Concurrence_ is the conjunction of two offices, which succeed one
another, so that a question arises as to which feast the Vespers belong
to; whether to the feast of the day or to the feast of the following
day, or whether the psalms should be of the feast and the remaining part
of the Vespers should be as the _Ordo_ so often notes (_a cap. de
seq._), from the _capitulum_ the office is taken from the following
feast.

The new rubrics contain five titles which make certain modifications in
the rules hitherto observed. We thus obtain a ready made division of the
subject:--

(1) Of the precedence of Feasts (Title II.).
(2) Of the accidental occurrence of feasts and their translation (Title
III.).
(3) Of the perpetual occurrence of feasts and their transfer (Title V.).
(4) Of the occurrence of feasts (Title V.).
(5) Of the commemorations (Title VI.) (Myers and Burton, _op. cit._).

The new rubrics without the aid of any commentator give pretty clear
notions of the laws of precedence, occurrence and commemoration. For
students in college these rules are expounded in detail with additions,
changes, exceptions. But for priests, long past the student stage, it is
difficult to undo the fixed liturgy lore of their student and early
priest life; and the need of such a book as _The New Psalter and its
Uses_ is, for those interested, a necessity. Even since the publication
of that book, changes have been made. For example, doubles, major or
minor and semi-doubles, which were perpetually excluded on their own day
were transferred to some fixed day. This is given in _The New Psalter
and its Uses_. But this has now been changed. In the case of feasts of
the universal Church, no translation is allowe