xt, which is really
distinct. (2) (Gr. [Greek: basis], strictly "stepping," and so a foundation
or pedestal) a term for a foundation or starting point, used in various
senses; in sports, _e.g._ hockey and baseball; in geometry, the line or
face on which a figure or solid stands; in crystallography, _e.g._ "basal
plane"; in surveying, in the "base line," an accurately measured distance
between the points from which the survey is conducted; in heraldry, in the
phrase "in base," applied to any figure or emblem placed in the lowest part
of a shield.

In chemistry the term denotes a substance which combines with an acid to
form a salt. In inorganic chemistry such compounds are almost invariably
oxides or hydroxides, and water in eliminated during the combination; but
in organic chemistry many compounds exist, especially ammonia derivatives,
which directly combine with acids. Chemical bases are consequently
antithetical to acids; and an acid is neutralized by a base with the
production of a salt. They reverse certain colour reactions of acids,
_e.g._ turn red litmus blue; this is termed an "alkaline reaction."

In architecture the "base" is the lowest member of a column or shaft. In
Egyptian and Greek architecture it is the raised slab in stone or cement on
which the primitive timber column was placed, to keep it dry. Afterwards it
was always reproduced in Egypt, even although the column, being in stone,
no longer required it; a custom probably retained because, being of a much
larger circumference than the lower part of the column, it gave increased
stability. In Assyrian architecture, where it served to carry wooden posts
or columns, it took the form of a large torus moulding with enrichments. In
Persian architecture the base was much higher than in any other style, and
was elaborately carved. In primitive Greek work the base consisted of the
stone plinth as found in Crete and Tiryns, and of three small steps at
Mycenae. In archaic Greek work it has already disappeared in the Doric
order, but in the Ionic and Corinthian orders it is more or less richly
moulded, the most elaborate examples being those found in the temple of
Apollo at Branchidae in Milesia. For the contour of the mouldings see
ORDERS. The Roman orders all have the favourite design known as the Attic
base. Romanesque bases were rude but vigorous copies of the old classic
base, and were often decorated with projections or spurs (Fr. _griffes_) at
the angles of