used in France, for carrying burthens on the back. It is slung over the arms by means of straps, and great weights are thus carried with much facility.

inch in length. Its chief food is the nectar of flowers, which it extracts with a humming noise like the bee, and suspends its nest from trees, laying two white eggs, the size of a pea.

HUMOURS OF THE EYE. Are three;

namely, the aqueous or watery humour, which lies in the fore part of the globe; the crystalline, or icy, next to the aqueous; and the vitreous, or glassy humour, which is larger than the rest, and fills the backward cavity of the eye.

HUNDRED WEIGHT. A measure of weight, equal to 112 lbs.; commonly denoted by the abbreviation cut.

HURDLES. Frames of split wood or willows wattled together, serving for sheepfolds or fences.

HURDLES (in Fortification.) Frames of osier twigs laden with earth, for making batteries.

HURRICANE. A storm of wind, frequent in the West Indies, which arises from the conflict of opposite winds.

HUSBANDRY. The practical part of agri.

HUSH-MONEY (in Law.) A bribe given to a person not to reveal something to which HOUSEHOLD. The whole of a family, in- he is privy.

cluding the mistress, children, and servants. HUSSARS. Hungarian horsemen, said to To a king's household belong several officers, be so called from the huzza or shout which as the lord steward, the lord chamberlain, &c. they gave at the onset in battle.

HYACINTH (in Botany.) A bulbous plant, water, whether it acts by impulse or pressure; the leaves of which are long and narrow, the but in an extended sense, it is that branch of stalk upright and naked, and the flower grow-mechanics which treats of the motion of liing on the upper part of a spike. quids or non-elastic fluids, and the forces with HYACINTH (in Mineralogy.) A sort of which they act on other bodies. pellucid gem, of a red colour, with a mixture of yellow.

crown were altogether of gold, the ball of gold, cone, another hyperbola will be formed, which being of the same bulk as the crown, would, is called the opposite hyperbola to the former. when immersed, raise the water just as high

as the crown immersed, but if it were wholly of silver, the ball of silver being immersed would raise the water no higher than the crown immersed; and if the crown was of gold and silver mixed in a certain proportion, this proportion would be discovered by the height to which the crown would raise the water higher than the gold and lower than the silver. The authors who have treated further on this subject may be found under the article HYDRO

measuring the degree of moisture and dryness of the atmosphere.

HYPERBOLE. An exaggerated represen

HYGROSCOPE. The same with hygro-tation of any thing.

meter.

In all names of instruments to which HYPOCHONDRIAC. One troubled with there are these two several terminations, as the spleen or melancholy. thermometer and thermoscope, the only difference is, that the first expresses something which measures, and the latter, which shows or exhibits to view.

HYMEN. The god of marriage. HYMENOPTERA. An order of insects in the Linnæan system, having membranaceous wings, as the gall-fly, the saw-fly, the bee, the wasp, the ichneumon, &c.

HYPOTHENUSE. The longest side of a right-angled triangle.

HYPOTHESIS. A principle taken for granted, in order to draw conclusions therefrom for the proof of a point in question.

HYSSOP. A plant with long narrow leaves, bearing a crest of flowers. It is doubtful whether this be the hyssop mentioned in Scripture.

HYPERBOLA. One of the curves formed HYSTERICS. Spasmodic, convulsive afby cutting a cone obliquely to its axis; and if fections of the nerves, to which women are the plane be produced so as to cut the opposite particularly subject.

I. and J.

I, the ninth letter of the alphabet, used as a JACK (in Natural History.) A kind of pike numeral signifies one, and stands for any num- that is very destructive in fishponds. bers of units as often as it is repeated, as, II, JACK, SMOKE. A very useful instrument two, III, three, &c. When placed before a in kitchens, sometimes turned by the force higher numeral, it diminishes it by one, as, with which smoke and rarefied air ascend in a IV, four, IX, nine; and when after, it increases chimney. The smoke-jack consists of a horiit by one, as, XI, eleven, XII, twelve, XIII, zontal wheel, the radii of which are placed obthirteen, &c. liquely, so as to permit the smoke to pass JACK (in Mechanics.) An instrument in through them; the axle then turns a small common use for raising very great weights of crank wheel, which works into another at any kind.

right angles, and at the end is a pulley with a chain to turn a spit set before the fire, with article intended to be turned and roasted. Many jacks are, however, turned by means of a weight, which pulls round a cylinder, and

any

JACK (among Mariners.) The flag which is hung out in the bowsprit end.