Horse-tail: A genus of the order of filices, belonging to the cryptogamia class of plants; and in the natural method ranking under the fifth order, Coniferae. There is a spike of peltated or shielded fructifications opening at the base. There are seven species; of which the most remarkable are, 1. The sylvaticum, or wood horse-tail. It grows in woods and moist shady places in many parts of England and Scotland. The stalk rises from 12 to 18 inches high, angular, and rough to the touch; the angles being edged with sharp spiculae, scarce visible without a microscope. The leaves grow verticillate, 12 or more in a whorl, and these whorls are about an inch distant from one another. The leaves are very slender, nearly quadrangular, about five inches long, pendent, and beset with several other secondary whorls, so that it resembles a pine-tree in miniature. Horses are very fond of this plant, and in some parts of Sweden it is collected to serve them as winter food. 2. The arvense, common or corn horse-tail, grows in wet meadows and corn-fields. The most remarkable property of this is, that its seeds, when viewed by a microscope, are seen to leap about as if they were animated. It has a very astringent and diuretic quality, and has been esteemed serviceable in the hematuria and gonorrhea, but is disregarded by the present practice. It is a troublesome plant in pastures; and disagreeable to cows, being never touched by them unless they are compelled by hunger, and then it brings on an incurable diarrhoea. It does not seem to affect horses or sheep. 3. The palustris, marsh horse-tail, or paddock pipe, is frequent in marshes and ditches. It is not so rough as the former, but is likewise prejudicial to cattle. 4. The fluvatile, or great river horse-tail, is frequent in shady marshes, and on the brink of stagnant waters. It is the largest of all the species, growing sometimes to the height of a yard, and near an inch in diameter. Haller tells us, that this kind of equisetum was eaten by the Romans; and Linnæus affirms, that oxen and rein-deer are fond of it, but that horses refuse it. 5. The hyemale, rough horse-tail, shave-grass, or Dutch rushes. This is much used by the whitewashers and cabinet-makers, under the name of Dutch rusher, for polishing their metals and wood. All the other species will answer this purpose in some degree, but the last better than any of the rest. In Northumberland the dairy-maids scour and clean their milk-pails with it. Some imagine, that if cows are fed with this species, their teeth will fall out.

EQUIITES, amongst the Romans, were persons of the second degree of nobility, immediately succeeding the senators in point of rank. The equites or knights were required to be possessed of 400 sesterces before they could be admitted into that order; and when the knights were so reduced as to fall short of the prescribed Equity, scribed revenue, they were expunged out of the equivalentarian list. The equestrian revenue just mentioned amounted to about 10,000 crowns.

Part of the ceremony whereby the honour of knighthood was conferred amongst the Romans was the giving of a horse; for every eques or knight had a horse kept at the public charge, he received also the stipend of an horsemanship to serve in the wars, and wore a ring which was given him by the state. The equites composed a large body of men, and constituted the Roman cavalry; for there was always a sufficient number of them in the city, and nothing but a review was requisite to fit them for service.

The knights at last grew too powerful, were a balance for the senate and people, neglected the exercises of war, and betook themselves to civil employments. The equites were liable to be punished by the censors, and to suffer degradation. They were degraded by taking from them the horse which was kept for each of them at the public charge; this was called equum admirae.