of these rocks are
principally oligoclase, muscovite, apatite and zircon. Biotite and all
ferromagnesian minerals rarely appear in them, and never are in
considerable amount. Riebeckite-granites (paisanites) have close
affinities to aplites, shown especially in the prevalence of alkali
felspars. Tourmaline also occurs in some aplites. The rocks of this
group are very frequent in all areas where masses of granite are known.
They form dykes and irregular veins which may be only a few inches or
many feet in diameter. Less frequently aplite forms stocks or bosses, or
occupies the edges or irregular portions of the interior of outcrops of
granite. The syenite-aplites consist mainly of alkali felspar; the
diorite-aplites of plagioclase; there are nepheline-bearing aplites
which intersect some elaeolite-syenites. In all cases they bear the same
relation to the parent masses. By increase of quartz aplites pass
gradually, in a few localities, through highly quartzose modifications
(beresite, &c.) into quartz veins. (J. S. F.)

APNOEA (Gr. [Greek: apnoia], from [Greek: a-], privative, [Greek:
pneein], to breathe), a technical term for suspension of breathing.

APOCALYPSE (Gr. [Greek: apokalupsis], disclosure), a term applied to the
disclosure to certain privileged persons of something hidden from the
mass of men. The Greek root corresponds in the Septuagint to the Heb.
_galah_, to reveal. The last book of the New Testament bears in Greek
the title [Greek: Apokalypsis Ioannou], and is frequently referred to as
the Apocalypse of John, but in the English Bible it appears as the
Revelation of St John the Divine (see REVELATION). Earlier among the
hellenistic Jews the term was used of a number of writings which
depicted in a prophetic and parabolic way the end or future state of the
world (e.g. _Apocalypse of Baruch_), the whole class is now commonly
known as Apocalyptic Literature (q.v.).

APOCALYPSE, KNIGHTS OF THE, a secret society founded in Italy in 1693 to
defend the church against the expected Antichrist. Agostino Gabrino, the
son of a merchant of Brescia, was its founder. On Palm Sunday 1693, when
the choir of St Peter's was chanting _Quis est iste Rex Gloriae?_
Gabrino sword in hand, rushed to the altar crying _Ego sum Rex Gloriae._
Though Gabrino was treated as a madman, the society flourished, until a
member denounced it to the Inquisition, who arrested the knights. Though
chiefly mechanics they always