PALLADIO, ANDREA, a famous Italian architect, was born at Vicenza, Nov. :10, 1518. After having studied with the greatest care the writings of Vitruvius, and the Monu ments of antiquity at Rome, he settled in his native city, and first acquired a reputation by his restoration of the basilica of Vicenza. Pope Paul III. then invited him to Rome, designing to intrust him with the execution of the works then going on at St. Peter's, bit, his holiness dying before the arrival of Palladio, the latter had to return home. lie was employedsfor many years in the construction of numerous buildings in Vicenza and the neighborhood, in all of which he displayed the most exquisite taste combined with the most ingenious and iniaginative ornamentation. Ilis style, known as the Pilladian, is it composite, and is characterized by great splendor of execution and justness of pro portion, and it exercised an immense influence on the architecture of Northern Italy. llis principal works are the Rotonda Capra. outside Vic •tiza; the pttlazzo Chiericado and the palazzo 'Ilene, in the city; the palazzo Barbara, at Maser in the Trevigiano, the Tea tro Olympico at Vicenza (his last work), the palazzo at Montagnana for Francesco Pisana; the churches of San Giorgio Maggiore and Ih Santissimo Redempiore at Venice, the atrium and cloister at the convent Della earn, and the facade of San Francesco della Vigna in the same city. Palladio died at Vicenza. Aug, 0, 1580. Tie wrote a work on architecture, which is highly prized. The best edition is that published at Vicenza in 4 vols., 1770.
(symb. Pd, eq. 53—new system. 100—spe. gray. 11.8) is one of the so called noble metals, which in its color and ductility closely resembles platinum. It is not fusible in an ordinary wind-furnace, but melts at a somewhat lower temperature titan the last-named metal, and when heated beyond its fusing point, it volatilizes in the form of a green vapor. It undergoes no change in the open air at ordinary temperatures;
but at a low red heat it becomes covered with a purple film, owing to superficial oxida tion. It is soluble in nitric and iodic acids, and in aqua regia. It combines readily with gold. which it has the property of rendering •brittle and white. (When it forms 20 per cent of the mass, the alloy is perfectly white.) When alloyed with twice its weight of silver, it forms a ductile compound, which has been employed for the construction of small weights; but for this purpose aluminium is superior. Professor :Uintr states that it " has been applied in a few cases to the construction of graduated scales for astronom ical instruments, for which, by its whiteness, hardness, and unalterability in the air, it is well adapted ;" its scarcity must, however, prevent its general use for this purpose.
It was discovered in 1803 by Wollaston in the ore of platinum, of which it seldom forms so much as 1 per cent Another source of this metal is the native alloy which it loans with gold in certain mines in Brazil, and which is termed ouro powlre ; and it is from this alloy that the metal is chiefly obtained.
Palladium forms with oxygen as protoxidc, PdO, which is the base of the salts of the metal: a binoxide, and according to smite chemist, a suboxide, Pd,..0. On expos ure to sufficient heat, these componnds give off their oxygen, and yield the metal. The salts of the protoxide are of a brown or red color.