Horn Silver. (Ag. Cl.) A native chloride of silver, which occurs either crystallized in cubes, or as a compact semi-transparent mass.

HORS-D’ŒUVRES. [Fr.] Syn. Assiettes, Fr. Small entrées, as ‘aiguillettes,’ ‘ragouts,’ plates of sardines, anchovies, or other relishes, served at dinner between the leading dishes. ‘Assiettes volantes’ (flying plates) are dishes handed round to the guests, but not placed on the table.

HORSE. Syn. Equus, L. This most useful quadruped belongs to the family Equidæ, distinguished by a single digit and hoof on each foot. The horse can scarcely be said to exist at the present day in its natural wild state, as the so-called ‘wild-horses’ of America and Asia are but the progeny of horses which have escaped from the haunts of civilisation. Of all animals the horse is most useful to man. Independently of its value as a beast of burden and draught, its skin, its hide, intestines, and bones, furnish us with leather, the thongs of whips, gut, grease, bone-black, manure, &c. The excrement, fat, and hoof were included in the Materia Medica of the Ph. L. 1618. The flesh is eaten in some countries, and was formerly esteemed to possess many virtues.

Injuries of a serious character, and even death, are often occasioned by horses running away, or becoming unmanageable. Various methods have been proposed to prevent accidents of this kind, and to place the animal entirely under the power of its rider or driver. In Russia, around the horse’s neck, near the neck strap, is placed a cord with a running knot. To this slip-noose is attached a pair of

reins, which always lie thrown over the dashboards, ready to be seized at once. When the horse starts, and becomes unruly, the gentleman takes up this cord, and tightens the horse’s throat, so that he cannot take breath. The most furious horse stops instantly, and will not fall or kick. See Bedding, Bran Mash, Broken Knees, Broken Wind, Clipping, Canker, Catarrh, Choking, Chorea, Cholic, Constipation, Corns, Crib-biting, Curb.

HORSE BALLS. See Veterinary Medicine.

HORSES, Condition Powder for. The principal ingredients were: Fenugreek, liquorice root, resin, brimstone, common salt, nitrate of potash, and a green powder, probably senna. It contained traces of calcium and magnesium carbonates; alumina, silica, and iron.

HORSE POW′ER. This term was first employed by James Watt to express a power capable of raising 33,000 lbs. one foot high per minute. The effective pressure on the surface of the piston was estimated at 7 lbs. to the square inch, and hence the area of the piston, in square inches, multiplied by 7, gave the gross effective moving pressure, and the space passed over by this piston in a minute gave the distance through which the pressure was exerted, or the weight was raised. From these data the horse power was easily calculated. In process of time improvements in the formation of boilers and steam engines increased the effective pressure on the piston, and, consequently, the power of the engine. In modern engines the actual power is commonly from 2 to 4 times greater than the nominal power, which is, however, still retained as the unit of power in commercial calculations.

HORSERAD′ISH. Syn. Armoracia radix. (B. P.). “The fresh root of Cochlearia Armoracia” (B. P.). Horseradish is pungent, acrid, stimulant, and rubefacient. It is also regarded as diaphoretic, diuretic, and antiscorbutic. It forms a useful masticatory in hoarseness, sore throat, and toothache. As a condiment, it provokes the appetite and assists digestion. Reduced to shreds (scraped horseradish), it forms a common and excellent accompaniment to roast beef. The root of aconite or wolfsbane, which somewhat resembles it in appearance, has occasionally been mistaken for it, with fatal results; the two are, however, readily distinguished from each other, as the taste of horseradish is warm and pungent, approaching that of mustard, whilst aconite is bitter, and its odour is earthy and disagreeable, and after a few minutes’ contact with the lips, tongue, and fauces, produces a sensation of numbness, and tingling. See Aconitum Napellus; under which article will be found engravings of the two roots. The root may be kept fresh for some time if buried in sand in a cool place. Horseradish powder is prepared from the roots gathered in November or December, and dried by a gentle heat or exposure to a current of dry air. It is used as a condiment.

HOR′TICULTURE. Syn. Gardening. The art of cultivating gardens. According to Loudon, horticulture differs from agriculture, chiefly in the comparatively limited space over which it extends, and in being conducted by manual labour; whilst the latter is performed jointly by human and animal labour, in fields, or on an extensive tract of land called a farm.