798 POZZO DI BORGO POZZUOLI including " Principles of Polity" (1752) ; "Ad- ministration of the Colonies" (1764); "De- scription of the Middle States of America" (1776); "A Memorial to the Sovereigns of Europe on the State of Affairs between the Old and the New World" (1780) ; "A Memo- rial to the Sovereigns of America" (1783); " Notices and Descriptions of the Antiquities of the Provincia Romana of Gaul" (1788); and " Intellectual Physics" (1795). POZZO DI BORGO, Carlo Andrea, count, a Rus- sian diplomatist of Oorsican origin, born at Alata, near Ajaccio, March 8, 1764, died in Pa- ris, Feb. 15, 1842. He completed his studies at the university of Pisa, and became an advocate at Ajaccio. His intimacy with the Bonaparte family came to an end in 1790, when he be- came a follower of Paoli. He represented Corsica in the French legislative assembly in l791-'2, but the discovery of a letter addressed by him to Louis XVI. obliged him to return to Corsica, where he was associated with Paoli in governing the island under English protec- tion, and became president of the council and secretary of state. In October, 1796, after the expulsion of the British, he fled to England. In 1798 he went to Vienna to effect a coalition between Austria and Russia against France, accompanied Suvaroff in his campaign of 1799, and in 1803 entered the Russian service as councillor of state. As commissioner he was despatched in 1805 to the Russian, English, and Neapolitan army in Italy, and subsequent- ly on various missions to Prussia and Austria. On account of the friendly relations entered into by Alexander and Napoleon, Pozzo left the Russian service in 1808, but reentered it after the close of the campaign of 1812. His whole influence was constantly exerted to keep Alexander steadfast in the war against France, and to gain Sweden for the allies, in which he succeeded. In the beginning of 1814 he went to London to secure the active cooperation of England, strenuously advocated the occupation of Paris, and in the congress of Chatillon op- posed accepting the offers of Napoleon. After the abdication of the emperor he was made Russian commissioner to the provisional gov- ernment of France, attended the congress of Vienna, and afterward was ambassador at the French court. He was slightly wounded at the battle of Waterloo. After the second restora- tion he was offered by Louis XVIII. the post of minister of the interior, but declined it, and as Russian ambassador signed the treaty of Paris in 1815. In 1823 he went on a mis- sion to Madrid, and after the accession of Nicholas in 1825 was created a count. He was ambassador at Paris when the revolution of 1830 broke out, and on the arrival of the news of the fall of Warsaw in September, 1831, the populace came near storming his residence. Subsequently he was ambassador in London till 1839, when he retired. He was never mar- ried. See Notice biographique sur le comte Pozzo di Borgo, by Vuhrer (Paris, 1842). CONSTITUENTS. Pozzuolana. Trass. Silica 44'5 57-0 Alumina 15-0 12'0 Lime 8-8 2'6 Magnesia . 4-7 1*0 Oxide of iron 12'0 5'0 Potash 1-4 7-0 Soda 4*0 1*0 Water and loss 9'6 14-4 Total ICO'O 100 '0 POZZEOLAJVA, a reddish, porous volcanic min- eral found near Pozzuoli, between Rome and Naples, and in other countries in the neighbor- hood of volcanoes. The catacombs of Rome were excavated in a large deposit of this argil- laceous sand, and it has been found in Sar- dinia, in the south of France, and in Rhenish Prussia near Andernach, where it is called trass. It is mainly a dehydrized silicate of alumina with other earths and alkalies, formed by the pouring of basaltic lava floods over argillaceous beds, or by similar natural pro- cesses. According to Berthier, the composi- tion of Italian pozzuolana and the German trass is as follows: Pozzuolana and trass are used for the prepara- tion of hydraulic cements in the countries where the deposits are found, and are also ex- ported. Their adaptability to the making of cements arises from the fact that the silica is in a condition to be easily acted on by calcic hydrate with which it is mixed, and also from its containing alkalies and oxide of iron, all of which unite in forming a mass which hardens in water. (See CEMENT.) POZZUOLI (anc. Puteoli), a town of Italy, on a bay of the same name, in the province and 6 m. W. of the city of Naples; pop. about 10,- 000. It is celebrated for its antiquities, which comprise an amphitheatre, one of the largest of its kind ; a Serapium, or temple of Serapis ; the upper part of a temple of Neptune ; a tem- ple of Diana, consisting of a bathing hall ; the villa Licastro, called the temple of Antinous after the statue discovered there; and ruins believed to be those of Cicero's villa. In the vicinity are many vestiges of ancient roads, covered with ruined tombs. About 1 m. N. E. of Pozzuoli is the Solfatara (anc. Forum Vulcani), the crater of a semi-extinct volcano. Aluminous waters springing from Mount Sic- cino, and known as the Pisciarella, are re- garded as identical with the mineral springs of antiquity. The ancient Puteoli was a Cam- panian city of Greek origin, which despite the distance from Rome virtually constituted its most useful harbor. Before Roman times, merchants of Tyre had establishments there; the natural advantages of the situation, and the protection of the harbor by a still visible mole, made Pozzuoli a great centre of trade and navigation. It was at the same time a favorite resort, like Baise on the opposite side of the bay, and prospered until after the reign of Honorius. Wars and repeated volcanic erup-
