o the motion of water
through pipes; worked by water_.

HYDRAU'LICS, _the science which treats of fluids in motion_.

HYDROCEPH'ALUS (Gr. n. _keph'ale_, the head), _dropsy of the head_.

HY'DROGEN (Gr. v. _gen'ein_, to beget), _a gas which with oxygen produces
water_.

HYDROG'RAPHY, _the art of maritime surveying and mapping_.

HYDROP'ATHY (Gr. n. _path'os_, feeling), _the water-cure_.

HYDROPHO'BIA (Gr. n. _phob'os_, fear), literally, _dread of water; canine
madness_.

HY'DROPSY, _a collection of water in the body_. ("Dropsy" is a contraction
of _hydropsy_).

HYDROSTAT'ICS, _the science which treats of fluids at rest_.

15. KRAT'OS, _rule, government, strength_.

ARISTOC'RACY (Gr. adj. _aris'tos_, best), _government by nobles_.

ARIS'TOCRAT, _one who favors aristocracy_.

AU'TOCRAT. See _au'tos_.

DEMOC'RACY (Gr. n. _de'mos_, the people), _government by the people_.

DEM'OCRAT, _one who upholds democracy; in the United States, a member of
the democratic party_.

THEOC'RACY, _government of a state by divine direction, as the ancient
Jewish state_.

16. LOG'OS, _speech, ratio, description, science_.

LOG'IC, _the science and art of reasoning_.

LOGI'CIAN, _one skilled in logic_.

LOG'ARITHMS (Gr. n. _arith'mos_, number), _a class of numbers that abridge
arithmetical calculations_.

ANAL'OGY, _a resemblance of ratios_.

AP'OLOGUE, _a moral fable_.

APOL'OGY, _a defense, an excuse_.

CAT'ALOGUE, _a list of names in order_.

CHRONOL'OGY. (See _chronos_.)

CONCHOL'OGY (Gr. n. _kon'chos_, a shell), _the science of shells_.

DEC'ALOGUE (Gr. _dek'a_, ten), _the ten commandments_.

DOXOL'OGY (Gr. n. _doxa_, glory), _a hymn expressing glory to God_.

EC'LOGUE, _a pastoral poem_.

ENTOMOL'OGY (Gr. n. _ento'ma_, insects, and v. _tem'nein_, to cut), _the
natural history of insects_.

EP'ILOGUE, _a short poem or speech at the end of a play_.

ETYMOL'OGY (Gr. _et'umon_, true source), _a part of grammar; the science of
the derivation of words_.

EU'LOGY, _praise, commendation_.

GENEAL'OGY (Gr. n. _gen'os_, birth), _history of the descent of families_.

GEOL'OGY (Gr. n. _ge_, the earth), _the science which treats of the
internal structure of the earth_.

MINERAL'OGY, _the science of minerals_.

MYTHOL'OGY (Gr. n. _mu'thos_, a fable), _a system or science of fables_.

ORNITHOL'OGY (Gr. n. _or'nis, or'nithos_, a bird), _the natural history of
birds_.

PATHOL'OGY (Gr. n. _path'os_, suf