or **Æquinoctial**, in *Astronomy*, a great and immoveable circle of the sphere, under which the equator moves in its diurnal motion.

The equinoctial, or æquinoctial line, is ordinarily confounded with the equator; but there is a difference, the equator being moveable and the equinoctial immoveable; the equator being drawn about the convex surface of the sphere, and the equinoctial on the concave surface of the *magnum orbis*.

Whenever the sun, in his progress through the ecliptic, comes to this circle, the days and nights are equal all over the globe; for then he rises due east and sets due west, which he never does at any other time of the year; and hence the denomination, from *æquus*, equal, and *nox*, night, quia æquat diem nocti.

The equinoctial, then, is the circle which the sun describes, or appears to describe, at the time of the equinoxes; that is, when the length of the day is everywhere equal to that of the night, which happens twice a year.

**Equinoctial Points** are the two points in which the equator and ecliptic intersect each other; the one, being in the first point of Aries, is called the *vernal point* or *equinox*; and the other, in the first point of Libra, is denominated the *autumnal point* or *equinox*.

**Equinoctial Dial**, a dial, the plane of which is parallel to that of the equinoctial. See *Dial*.

**Equinox**, or **Æquinox**, in *Astronomy*, the time when the sun enters one of the equinoctial points.

The equinoxes happen when the sun is in the equinoctial circle, and the days are equal to the nights throughout the world, which is the case twice a year; namely, about the 20th of March and the 23rd of September, the former being the vernal and the latter the autumnal equinox.

**Equipollence**, in *Logic*, is when there is an equivalence between any two or more terms or propositions; that is, when they amount to the same thing, though they express it differently. Such terms or propositions are said to be *equipollent*.

**Equirria**, in *Antiquity*, a festival instituted by Romulus, and celebrated on the 27th of February, in honour of Mars. There were horse-races at this festival.

**Equites**, an order of men in the commonwealth of Rome, to which we can furnish no exact parallel in modern times. They seem, indeed, to have resembled in some degree the gentry of England; with this difference, however, that they enjoyed peculiar privileges, and were more of a separate caste than any body of men which can now be pointed out. Their origin goes back to the earliest times of Roman history, though we can perceive, even from the legendary statements of Livy and Dionysius, that their constitution and mode of selection had been changed in the course of ages. During the reign of the kings they evidently appear to have been of noble birth, the younger branches of patrician families. This we may infer from the statement of Polybius (vi. 20), when he says that the knights *nox* are chosen according to fortune, evidently intimating that their selection had depended on a different principle at a previous period. Romulus is said to have divided them into three centuries; and the very names of Rammenses, Titienes, and Lucerces, by which he designated them, point out distinctly their high origin. Both Tullus Hostilius and Tarquinius added to their number; but it was Servius Tullius (576 B.C.) who first organised them into a distinct body, and compelled the state to contribute annually to their maintenance. It is difficult to perceive in what way we are to explain the statement of Livy (i. 43), that the sum of ten thousand pounds of brass was given to each for the purchase of a horse; an enormous sum, when compared with that at which oxen and sheep were rated in the table of penalties. They were bound of course to be provided with a noble steed, and may have been obliged to replace it if it fell from any casualty in war. The accoutrements, too, and a slave to take charge of it, were possibly all included in this large sum. But whether, when the censor ordered the knight to sell his horse, it was the intention that the outfit money should be refunded to the state, we have no means of determining. Livy tells us also that a tax was imposed on each *vidua*, of two thousand pounds of brass to maintain a knight's horse. This certainly sounds very strange; for it seems inconceivable that there should have been such a large number of rich widows; and even though we understand by the word *vidua* every single woman, maiden as well as widow, we do not think that we thereby get out of the difficulty.

As early as 400 B.C., we find that a certain fortune was required to enable a man to be raised to the rank of eques. In that year, at the siege of Veii, we are told that those who possessed the requisite fortune, but to whom horses had not been assigned, offered to provide these at their own expense. This proposal was accepted; and then it was, according to Livy (v. 7), that they first received regular pay. In 363 B.C., the censors Q. Fabius and P. Decius established a law, by which it was ordained that every fifth year a procession of the equites should take place, and that those who had misconducted themselves should be degraded from their rank. They now evidently became a very powerful body in the state; yet in 186 B.C., we find it allowed as a reward to P. Eubius, that the censor should not assign him a public horse, and thereby compel him to serve as an eques against his will. This proves that the duties must have been burdensome, and regarded by many with distaste. In the later times of the republic they increased in power and consequence, when the judicial functions were transferred from the senate to the body of equites by the Sciponian law, passed by C. Gracchus about 123 B.C.; and a short time afterwards they became the farmers of the public revenues, which enabled them to amass immense riches. Sylla deprived them of their judicial powers; but they now possessed too much influence in the state to be excluded from the higher and more dignified offices. After his death they were again admitted to their former power, which, however, they shared with the senate.

Towards the end of the republic, and under the emperors, the fortune requisite for an eques seems to have been four hundred sesterces, equal to about L3229 of our money; and even at this time knights' horses were furnished by the state, as we find by ancient inscriptions of that period. (Gruter. Inscr. 404.)