The illustrious discoverer of the true planetary motions, whose features are represented on the accompanying plate, lived during the latter part of the fifteenth century, and the first half of the following one. Notwithstanding the success and celebrity of the theory which still bears his name, the materials are very scanty for personal details regarding his life and character. This ignorance is not the result of recent neglect. A century had scarcely elapsed from the time of his death, when Gassendi, who, at the request of the poet Chapelain, undertook to compile an account of him, was forced to preface it by a similar declaration. Whilst Europe rang from one end to the other with the fierce dispute to which the new views of the relation and motions of the heavenly bodies gave rise, the character, the situation and manner of life, almost the country, of the great author of the controversy, remained unknown to the greater number of his admirers and opponents. Even the name of the discoverer of the Copernican system now appears strange, except in the Latinised form of Copernicus, in which alone it occurs in his own writings and in those of his commentators. Nicolas Cöpernik[1], to use his genuine appellation, was a native of Thorn, a city of Polish Prussia, situated on the river Weichsel or Vistula. He was born in the year 1473. Little is known of his parents, except that his father, whose name also was Nicolas, was a surgeon, and, as it is believed, of German extraction. The elder Cöpernik was undoubtedly a stranger at Thorn, where he was naturalized in 1462: he married Barbara, of the noble Polish family of Watzelrode. Luke, one of her brothers, attained the high dignity of Bishop of Ermeland in the year 1489, and the prospects of advancement which this connection held out to young Cöpernik, probably induced his father to destine him to the ecclesiastical profession. He acquired at home the first elements of a liberal education, and afterwards graduated at Cracow, where he remained till he received the diploma of Doctor in Arts and Medicine from that university. He is said to have made considerable proficiency in the latter branch of study; and possessed, even in more advanced life, so high a reputation for skill and knowledge, as to produce an erroneous belief that he had once followed medicine. Footnote 1: The authority for this manner of spelling the name is Hartknoch, Alt und Neues Preussen. The inscription, Nicolao Copernico, which appears on the plate, is a literal copy of the inscription on the original picture. [Illustration: _Engraved by E. Scriven._ NICOLAO COPERNICO. _From a Picture in the possession of the Royal Society, presented by D^r. Wolf, of Dantzic, June 6, 1770._ Under the Superintendance of the Society for the Diffusion of Useful Knowledge. _London. Published by Charles Knight, Pall Mall East._ ]