The strata all over the earth, which were formed at the same time,
are said to belong to the same geological horizon.
Le Conte.
4. (Painting) The chief horizontal line in a picture of any sort, which
determines in the picture the height of the eye of the spectator; in an
extended landscape, the representation of the natural horizon
corresponds with this line.
Apparent horizon. See under Apparent. -- Artificial horizon, a level
mirror, as the surface of mercury in a shallow vessel, or a plane
reflector adjusted to the true level artificially; -- used chiefly with
the sextant for observing the double altitude of a celestial body. --
Celestial horizon. (Astron.) See def. 2, above. -- Dip of the horizon
(Astron.), the vertical angle between the sensible horizon and a line
to the visible horizon, the latter always being below the former. --
Rational horizon, and Sensible horizon. (Astron.) See def. 2, above. --
Visible horizon. See definitions 1 and 2, above.
Hor`i*zon"tal (?), a. [Cf. F. horizontal.] 1. Pertaining to, or near,
the horizon. "Horizontal misty air." Milton.
2. Parallel to the horizon; on a level; as, a horizontalline or
surface.
3. Measured or contained in a plane of the horizon; as, horizontal
distance.
Horizontal drill, a drilling machine having a horizontal drill spindle.
-- Horizontal engine, one the piston of which works horizontally. --
Horizontal fire (Mil.), the fire of ordnance and small arms at
point-blank range or at low angles of elevation. -- Horizontal force
(Physics), the horizontal component of the earth's magnetic force. --
Horizontal line (Descriptive Geometry & Drawing), a constructive line,
either drawn or imagined, which passes through the point of sight, and
is the chief line in the projection upon which all verticals are fixed,
and upon which all vanishing points are found. -- Horizontal parallax.
See under Parallax. -- Horizontal plane (Descriptive Geometry), a plane
parallel to the horizon, upon which it is assumed that objects are
projected. See Projection. It is upon the horizontal plane that the
ground plan of the buildings is supposed to be drawn. -- Horizontal
projection, a projection made on a plane parallel to the horizon. --
Horizontal range (Gunnery), the distance in a horizontal plane to which
a gun will throw a projectile. -- Horizontal water wheel, a water wheel
in which the axis is vertical, the buckets or floats revolving in a
horizontal plane, as in most turbines.
Hor`i*zon*tal"i*ty (?), n. [Cf. F. horizontalitÈ.] The state or quality
of being horizontal. Kirwan.
Hor`i*zon"tal*ly, adv. In a horizontal direction or position; on a
level; as, moving horizontally.
||Hor`mo*go*ni"um (?), n. [NL., fr. Gr. &?;a chain + &?; generation.]
||(Bot.) A chain of small cells in certain algÊ, by which the plant is
||propagated.
Horn (?), n. [AS. horn; akin to D. horen, hoorn, G., Icel., Sw., & Dan.
horn, Goth. ha˙rn, W., Gael., & Ir. corn, L. cornu, Gr. &?;, and perh.
also to E. cheer, cranium, cerebral; cf. Skr. Áiras head. Cf. Carat,
Corn on the foot, Cornea, Corner, Cornet, Cornucopia, Hart.] 1. A hard,
projecting, and usually pointed organ, growing upon the heads of
certain animals, esp. of the ruminants, as cattle, goats, and the like.
The hollow horns of the Ox family consist externally of true horn, and
are never shed.
2. The antler of a deer, which is of bone throughout, and annually shed
and renewed.
3. (Zoˆl.) Any natural projection or excrescence from an animal,
resembling or thought to resemble a horn in substance or form; esp.:
(a) A projection from the beak of a bird, as in the hornbill. (b) A
tuft of feathers on the head of a bird, as in the horned owl. (c) A
hornlike projection from the head or thorax of an insect, or the head
of a reptile, or fish. (d) A sharp spine in front of the fins of a
fish, as in the horned pout.
4. (Bot.) An incurved, tapering and pointed appendage found in the
flowers of the milkweed (Asclepias).
5. Something made of a horn, or in resemblance of a horn; as: (a) A
wind instrument of music; originally, one made of a horn (of an ox or a
ram); now applied to various elaborately wrought instruments of brass
or other metal, resembling a horn in shape. "Wind his horn under the
castle wall." Spenser. See French horn, under French. (b) A drinking
cup, or beaker, as having been originally made of the horns of cattle.
"Horns of mead and ale." Mason. (c) The cornucopia, or horn of plenty.
See Cornucopia. "Fruits and flowers from AmalthÊa's horn." Milton. (d)
A vessel made of a horn; esp., one designed for containing powder;
anciently, a small vessel for carrying liquids. "Samuel took the hornof
oil and anointed him [David]." 1 Sam. xvi. 13. (e) The pointed beak of
an anvil. (f) The high pommel of a saddle; also, either of the
projections on a lady's saddle for supporting the leg. (g) (Arch.) The
Ionic volute. (h) (Naut.) The outer end of a crosstree; also, one of
the projections forming the jaws of a gaff, boom, etc. (i) (Carp.) A
curved projection on the fore part of a plane. (j) One of the
projections at the four corners of the Jewish altar of burnt offering.
"Joab . . . caught hold on the horns of the altar." 1 Kings ii. 28.
6. One of the curved ends of a crescent; esp., an extremity or cusp of
the moon when crescent- shaped.
The moon Wears a wan circle round her blunted horns.
Thomson.
7. (Mil.) The curving extremity of the wing of an army or of a squadron
drawn up in a crescentlike form.
Sharpening in mooned horns Their phalanx.
Milton.
8. The tough, fibrous material of which true horns are composed, being,
in the Ox family, chiefly albuminous, with some phosphate of lime;
also, any similar substance, as that which forms the hoof crust of
horses, sheep, and cattle; as, a spoon of horn.