SANGALLO, ANTONIO DE, a celebrated architect, born in the 15th century, in the territory of Florence. his father, Antonio Picconi, was a cooper by trade, and Antonio was brought up to the business of a joiner. Having, how ever, two uncles, Guiliano and Antonio Sangallo, architects, of considerable reputation at Rome, he placed himself under their tuition, and assumed their name. He soon exhibited considerable talents, and his progress in the art made him known to Bramante, who, in 1512, entrusted to him the execution of several works. He soon obtained employment from some Cardinals ; and in the pontificate of Leo X, when his uncle Giuliano quitted Rome, he was appointed his suc cessor as architect of St. Peter's, in conjunction with Raphael. I le also manifested great skill as an engineer ; and Leo adopted a plan which he gave for the fortification of Civita Vecchia. Under Clement VII. he was employed in enlarg ing and embellishing the Vatican Palace, and in repairing the fortifications of Parma and Placentia. He is also cele brated for the construction of a remarkable well at Orvietto which had two staircases for the descent and ascent of beasts of burden. He enjoyed the favour of Paul III., who employed him in many important works as architect and engineer ; and when Charles V. visited Rome after his Tunisian expedition, • Songallo had the planning of the triumphal decorations with which he was received. The Pauline chapel, and the mag
ntheent staircases by which the chapels of the Vatican com municate Nrith St. Peter's, were of his construction. The grandest effort of his genius was a wooden model of St. Peter's, which, however, was not closely followed. As he was noted for the solidity of his building, he was employed in strengthening the foundations of the Vatican and of the great columns which support the cupola of St. Peter's. Being engaged by the pope to survey the inundations of the lake of Marmora, tila heat and the exhala tions from the foul water caused a disease, of which he died in the year 15.16.
SAP (from the Italian zappare, to undermine), in building, a term used when a trench is opened in the ground at the foot of a wall, &c., so as to bring all at once for want of support.
To demolish the thick firm walls of old•astles, &e, sapping is much the readiest way.
SAP, in the military art, denotes a work carried on under cover of gabions and fascines on the flank, and mantelets, or stuffed gabions, on the front, to gain the descent of a ditch, conntersearp, or the like.
It is performed by digging a deep trench, descending by steps from top to bottom, under a corridor, carrying it as for as the bottom of the ditch, when that is dry ; or as for as the surface of the water, when wet.