ZIG-ZAG COURSE. Working to windward by very short tacks or angular turning boards.

ZODIAC. A broad zone or belt of the heavens, the middle of which is the ecliptic, extending 9 on either side of it. It is divided into twelve signs, each measuring 30 along the ecliptic.

ZODIACAL LIGHT. A pyramidal cone of light, apparently emanating from the rising and setting sun, commonly seen in the tropics; in higher lat.i.tudes most visible about the time of the equinoxes.

ZOLL, OR SAUL. An Indian timber, much used in the construction of country vessels.

ZONE. _See_ BELT.

ZONE OF DECLINATION. A belt of the heavens included between certain parallels of declination.

ZONES, IN GEOGRAPHY, are longitudinal belts into which the surface of the earth is divided, according to their various relation to the sun's apparent motion. They are--the _torrid_ or _equatorial zone_, bounded by the two _tropics_ (which see), to every part of which, at some time or other, the sun is vertical; the _frigid zones_, from the poles to the polar circles, to every part of which in succession, periodically, the sun is at mid-day below the horizon; and the _temperate zones_, intermediate between the two former, to all of which the sun rises every day in the year.

ZOOPHYTE. A term compounded of two Greek words, signifying animal-plant, vaguely applied to various low forms of animal organizations, as the sea-anemones and coral animals, which present a certain superficial resemblance to plants.

ZOp.i.s.sA. Tar or pitch sc.r.a.ped off the bottoms of old s.h.i.+ps, and thought to be astringent and good for ulcers. Also, a highly preservative varnish in use by the ancients for s.h.i.+ps' bottoms, sarcophagi, &c.

ZUHN. A species of Indian rush, from which an inferior kind of cordage and canvas is made.

ZUMBRA. A Spanish skiff or yawl.