Heraldry, is accounted one of the most noble bearings in armory; and, according to the learned in this science, ought to be given to none but such as greatly excel in the virtues of generosity and courage, or have rendered singular service to their sovereigns; in which case they may be allowed a whole eagle, or an eagle naisant, or only the head or such other parts as may be judged most agreeable to their exploits.

The eagle has been borne as an ensign or standard by several nations. The first who seem to have assumed the eagle were the Persians, according to the testimony of Xenophon; but subsequently it was adopted by the Romans, who, after a great variety of standards, at length fixed on the eagle, in the second year of the consulate of C. Marius, having till that period used indifferently wolves, leopards, and eagles, according to the humour of the commander. The Roman eagles, it must be observed, were not painted on a cloth or flag, but were figures in relief, formed of silver or gold, and borne on the tops of pikes; the wings being displayed, with frequently a thunderbolt in the talons. Under the eagle on the pike were piled bucklers, and sometimes crowns.

Constantine is said to have been the first who introduced the eagle with two heads, to intimate, that though the empire seemed divided, it had yet only one body. Others say that it was Charlemagne who resumed the eagle as the Roman ensign, and added to it a second head; but that opinion is destroyed by an eagle with two heads, observed by Lipsius on the column of Antoninus, as also by the eagle's having only one head on the seal of the golden bull of the Emperor Charles IV. The conjecture, therefore, of Menestrier appears more probable; namely, that the emperors of the East, when there were two on the throne at the same time, struck their coins with the impression of a cross with a double traverse, which each of them held in his hand, as being the symbols of the Christians; and that they did the like with the eagle in their ensigns, and instead of doubling, joined them together, representing them with two heads; a practice in which they were followed by the emperors of the West. But this conjecture of Menestrier is not confirmed by ancient coins, without which Papebroche inclines to think the use of the eagle with two heads to have been merely arbitrary, though he admits it to be probable that it was first introduced on occasion of there being two emperors on the same throne.

The eagle on medals is, according to Spanheim, a symbol of divinity and providence, and, according to all other antiquaries, of empire. The princes on whose medals it is most usually found are the Ptolemies, and the Seleucidae of Syria. An eagle with the word consecratio expresses the apotheosis of an emperor.

Astronomy, is a constellation of the northern hemisphere, having its right wing contiguous to the equinoctial. See Aquila.

White Eagle, is a Polish order of knighthood, instituted in 1325 by Vladislav V. on marrying his son Casimir to a daughter of the grand duke of Lithuania. The knights of this order were distinguished by a gold chain which they wore on the stomach, and to which was suspended a silver eagle crowned.

Black Eagle, a similar order instituted in 1701 by the elector of Brandenburg, on his being crowned king of Prussia. The knights of this order wore an orange-coloured ribbon, to which was suspended a black eagle.

Eagle Island, an island in the South Pacific Ocean, near the north-east coast of New Holland, between Lizard Island and Cape Flattery. Lat. 14. 32. S.