The Sailor's Word-Book / An Alphabetical Digest of Nautical Terms, including Some More Especially Military and Scientific, but Useful to Seamen; as well as Archaisms of Early Voyagers, etc.

by W. H. Smyth

HOPPO. The chief of the customs in China.

HOPPO-MEN. Chinese custom-house officers.

HORARY ANGLE. The apparent time by the sun, or the sidereal time of the moon, or planets, or stars, from the meridian.

HORARY MOTION. The march or movement of any heavenly body in the space of an hour.

HORARY TABLES. Tables for facilitating the determination of horary angles.

HORIE-GOOSE. A northern name for the Anser bernicla, or brent-goose.

HORIOLÆ. Small fishing-boats of the ancients.

HORIZON. The apparent or visible circle which bounds our vision at sea; it is that line which is described by the sky and water appearing to meet. This is designated as the sensible horizon; the rational, or true one, being a great circle of the heavens, parallel to the sensible horizon, but passing through the centre of the earth.

HORIZON-GLASSES. Two small speculums on one of the radii of a quadrant or sextant; the one half of the fore horizon-glass is silvered, while the other half is transparent, in order that an object may be seen directly through it: the back horizon-glass is silvered above and below, but in the middle there is a transparent stripe through which the horizon can be seen.

HORIZONTAL. A direction parallel to the horizon, or what is commonly termed lying flat. One of the greatest inconveniences navigators have to struggle with is the frequent want of a distinct sight of the horizon. To obviate this a horizontal spinning speculum was adopted by Mr. Lerson, who was lost in the Victory man-of-war, in which ship he was sent out to make trial of his instrument. This was afterwards improved by Smeaton, and consists of a well-polished metal speculum about 31⁄2 inches in diameter, inclosed within a circular rim of brass, so fitted that the centre of gravity of the whole shall fall near the point on which it spins. This is the end of a steel axis running through the centre of the speculum, above which it finishes in a square for the convenience of fitting a roller on it, bearing a piece of tape wound round it. The cup in which it spins is made of agate flint, or other hard substance. Sextants, with spirit-levels attached, have latterly been used, as well as Becher's horizon; but great dexterity is demanded for anything like an approximation to the truth; wherefore this continues to be a great desideratum in navigation.