his sons; and the largest is still popularly called the 'Treasury of Atreus.'
ATREUS, TREASURY OF. A famous subterranean structure at Mycenæ, so called on the
authority of Pausanias. It is also popularly
called the 'Tomb of Agamemnon.' It is the
largest of the vaulted tombs called 'bee-hive'
tombs from the method of vaulting in which the
arch is formed by projecting horizontal layers of
stones narrowing to the top. The building con-
sists of a circular chamber. 50 feet wide and
high, connected with a small square room, both
covered by the material removed in the process
of building. It is approached by an entrance
passage of masonry 115 feet long, leading to a
deep doorway richly ornamented.
ATRI, ii'tre (anciently, Hadria). An epis-
copal city in the Province of Teramo. Italy, 8
miles from the Adriatic and from Jhitignano,
which is on the Bologna-Brindisi Railway, 79
miles south of Ancona. The cathedral has inter-
esting frescoes, and a Fifteenth-Century paint-
ing of the Madonna adoring the Child. The
Campanile is over 200 feet high. There are a
few ruins of ancient walls and buildings, and
south of the city are grottoes probably once used
as prisons. The manufactures are silk, soap,
and licorice. Population (commune), in 1881,
10,642; in 1901, 13,448.
AT'RIPLEX (Lat., from Gk. irpdcltaivs, at ra-
phaxj/s, the orach) . The name of a genus of plants
of the order Chenopodiaceæ. The species are nu-
merous, and are found in nearly all tropical and
temperate climates. Many of them are weeds,
but a number have come into notice as valu-
able forage plants for the hot alkali regions
of Australia and California. For this purpose
Atriplex semibaccata and Atriplex leptocarpa
are among the most promising. They are com-
monly known as saltbushes, because they grow
in saline regions, where no other valuable plant
will survive.
ATRIUM (Lat., a hall; literally, 'dark-
room,' from ater, black, dark, referring to the
smoke from the stove or hearthstone. See
below). In Roman architecture, the one large
apartment of the primitive Italic and Roman
house ; the general room which served for
kitchen, dining-room, reception and sleeping
room. In it was the hearthstone, and the nvip-
tial couch remained there as a symbol, even
after the addition of bedrooms around it. As
the Roman house became more sumptuous, small
rooms were multiplied around this central hall,
which remained immediately opposite the en-
trance, and then took the name also of cavæ-
dium. There were different kinds of atria: (1)
The earliest kind, with the solid roof (atrium
testudinatum); (2) next, the Tuscan atrium
(tuscanicum), which became the national type
before the close of the Republic, with a square
opening (compluvium) in the centre for ad-
mitting light. The roof sloped inward, so that
rain-water flowed into a basin (impluvium) be-
neath the opening. With the enlargement of
house and atrium came (3) the tetrastyle
atrium (tetrastylum), with four columns sup-
porting the central opening: and finally, with
the further sumptuousness of the times of Cicero
and Augustus, came (4) the Corinthian atrium,
where the four columns are multiplied into a real
colonnade; and in this form the atrium is in-
distinguishable from a peristyle court, a private
cloister. There was another early kind of
atrium, used especially for winter apartments,
in which the roof slanted upward like our
roofs, instead of downward toward the centre,
and shed the water instead of collecting it
(displuviatum). The patrician and richer
equestrian houses of the late Republic and Em-
pire usually had two atria — first the old-fash-
ioned kind (1; 2), for the transaction of busi-
ness, and in front of it the shops; and beside and
beyond it, the alæ and tablinum; then a peristyle
atrium, with columns, with rooms opening on to
it, where the family life was carried on. The
later atria were beautifully decorated with fres-
coes and sculptures, vases and fountains. The
best-preserved atria of all kinds are in the
houses of Pompeii. The term was also some-
times used of religious or public buildings, in
the form of courts, such as the Atrium Vestæ,
attached to the house and temple of Vesta, and
the Atrium Liberatis, which contained the first
library founded in Rome.
In Christian antiquities, the atrium was a large columnar open court in front of the basilical churches, used for meetings or promenades, and even for agapæ and fairs. In the centre stood the fountain for ablutions. In it gathered the penitents who were not allowed in the church. These atria went out of use in the early Middle Ages. Those at Parenzo (Sixth Century), Sant' Ambrogio, Milan (Ninth Century), San Clemente, Rome (Eleventh and Twelfth centuries), and in the cathedrals of Capua and Salerno are the best preserved. In the monastic architecture of the early and Middle Ages, the cloister was evidently the atrium moved from the front to the side of the church, and reserved for the use of the monks. See Cloister.
ATROPATENE, at'r6-pa-te'ne (Gk. 'Arpo-
Trarrii/t]). The ancient name of the mountainous
Persian Province of Azerbaijan, or Adarbaij.an,
to the west of the Caspian Sea. Its name is
said to be due to Atropates, whom Alexander
placed over the district in B.C. 328. In Pahlavi
(q.v. ) the name appears as Ataro-patakan. The
principal city of the province, now as in an-
tiquity, is Urumiah, on the lake of the same
name.
AT'ROPHY (Gk. dTpo(pla, atrophia, want
of nourishment; from d, « priv. + rpoip'r), traplir,
nourishment). A morbid condition of animal
or vegetable life, resulting in deficient nutrition
of the body, or part of the body, and a conse-
quent decay and waste of its substance. The
term is not applied to the mere withholding the requisite supply of nutriment, but to the condition produced by various diseases that affect the body. See Nutrition; Digestion, Organs of; Dyspepsia; Hypertrophy.
AT'ROPINE (derived from Atropos), or Daturine, CijHjiNOa. An alkaloid prepared from the deadly nightshade (Atropa belladonna). The plant contains the alkaloid hyoscyamine, which is readily converted into atropine on addition of potash to the juice. The atropine thus produced is extracted by shaking the alkaline liquid with chloroform. It is then transferred from the chloroform solution into sulphuric acid by simply shaking the chloroform solution with the diluted acid; finally,
