LEOPOLD, Count. This eminent writer was born of a noble family at Ferrara in 1767; and distinguished himself in physical and mathematical science at Pavia, where he completed his academica career. In 1795 we find him settled at Modena, where he was employed by the government; and for some time he was its representative at Taurin; but he resigned this post in 1808 on being appointed president of the academy of the fine arts at Venice. He was now in his true element, and published very important works connected with the fine arts. His treatise on the Beautiful appeared soon after his removal to Venice; and from 1816 to 1818 he published his great work "Storia della Scultura dal suo Risorgimento in Italia al Secolo di Napoleone," in 3 vols., folio. This excellent work gives a luminous view of the progress of modern sculpture, carrying down its history to our own times, and thus supplying the portions since the time of Winckelmann and D'Aigocourt. He also produced a treatise on copper-engraving, "Memorie per servire alla Storia della Calcografia;" and the two magnificent folio volumes "On the Most Conspicuous Edifices of Venice" owe much of their value to his pen, though in this work he had the assistance of Selva and Diedo. His systematic catalogue of his own rich library, in two 8vo volumes, shows the immense collection he had formed of works illustrative of every branch of the fine arts, and the use he had made of them. In short, he may be regarded as one of the most learned and assiduous writers that ever handled such subjects. He also possessed considerable poetic powers, as appears by his first publication, "Le Ore del Giorno," published at Palermo in 1790; the beautiful and correct edition of Lallemand, in 14 vols., 12mo, Paris, 1768; and the magnificent but as yet uncompleted edition begun at Naples 1777. Cicognara died at Venice on the 5th March 1834.

CIDUTA, hemlock, the juice of which was the famous elixir of the Athenians, used in the execution of criminals. Thus, too, perished Socrates, b.c. 399. (Plat. Phaed.)

CID, Th., (from the Arabic El Seid, the Lord,) a name given to Rodrigo Diaz de Bivar, the national hero of Spain. See POETRY.