GUITARRA, a musical instrument of the strung kind, with five double rows of strings; of which those that are brats are in the middle, except it be for the burden, an octave lower than the fourth. ——This instrument was first used in Spain and by the Italians. In the former country it is still greatly in vogue. There are few of that nation who cannot play on the guitar; and with this instrument they serenade their mistresses at night. At Madrid, and other cities in that country, it is common to meet in the streets young men equipped with a guitar and a dark lantern, who, taking their station under the windows, sing, and accompany their voices with this instrument; and there is scarce an artificer or day-labourer in any of the cities or principal towns who does not entertain himself with his guitar.

GULDENSTAEDT, JOHN ANTHONY, physician and naturalist, was born at Riga, April 26, 1745; received the rudiments of his education in that town; and in 1763 was admitted into the medical college of Berlin. He completed his studies at Frankfort upon the Oder, and in 1767 received the degree of M. D. in that university. On account of his knowledge of foreign languages, and the considerable progress he had made in natural history, he was considered as a fit person to engage in the expeditions which were planned by the Imperial academy. Being invited to St Petersburg, he arrived in that city in 1768, was created adjunct of the academy, and afterwards, in 1770, member of that society, and professor of natural history. In June 1768 he set out upon his travels, and was absent seven years. From Moscow, where he continued till March 1769, he passed to Voronezt, Tzaritzin, Afracan, and Kilfar, a fortress upon the western shore of the Caspian, and close to the confines of Persia. In 1770 he examined the districts watered by the rivers Terek, Sunhfa, and Alksai, in the eastern extremity of Caucasus; and in the course of the ensuing year penetrated into Offetia, in the highest part of the same mountain; where he collected vocabularies of the languages spoken in those regions, made inquiries into the history of the people, and discovered some traces of Christianity among them. Having visited Cabarda and the northern chain of the Caucasus, he proceeded to Georgia, and was admitted to an audience of Prince Heraclius, who was encamped about ten miles from Teflis. Having passed the winter here, and in examining the adjacent country, he followed in spring the prince to the province of Kakhtia, and explored the southern districts inhabited by the Turcoman Tartars in the company of a Georgian magnate, whom he had cured of a dangerous disorder. In July he passed into Imeretia, a country which lies between the Caspian and Black seas, and is bounded on the east by Georgia, on the north by Offetia, on the west by Mingrelia, and on the south by the Turkish dominions. He penetrated into the middle chain of Mount Caucasus, visited the confines of Mingrelia, Middle Georgia, and Eastern and Lower Imeretia; and, after escaping many imminent dangers from the banditti of those parts, fortunately returned to Kilfar on the 18th of November, where he passed the winter, collecting various information concerning the neighbouring Tartar tribes of the Caucasus, and particularly the Lefgees. In the following summer he journeyed to Cabarda Major, continued his course to Mount Beshiton, the highest point of the first ridge of the Caucasus; inspected the mines of Madshar, and went to Tcherkask upon the Don. From thence he made expeditions to Azof and Taganrog, and then, along the new limits to the Dnieper. He finished this year's route at Kremenfhuik, in the government of New Russia. In the ensuing spring he was proceeding to Crim Tartary; but receiving an order of recall, he returned through the Ukraine to Moscow and St Petersburg, where he arrived in the month of March 1775. Upon his return, he was employed in arranging his papers; but before he could finish them for the press, was seized with a violent fever, which carried him to the grave in March 1781. His writings which have been hitherto published consist of a number of curious treatises, of which a list is given in Coxe's Travels, vol. i. p. 162.