Tycho, an illustrious astronomer, descended of a noble family, originally of Sweden but settled in Den- mark, was born on the 14th December 1546, at Knudstorp, in the county of Schonen. He learned Latin at the age of seven, and studied five years under private tutors. On the death of his father his uncle sent him, in April 1559, to study philosophy and rhetoric at Copenhagen. The great eclipse of the sun, on the 21st of August 1560, happening at the precise time foretold by astronomers, he began to look upon astronomy as something divine; and having purchased the Ephemerides of Stadius, he gained some notion of the theory of the planets. In 1562 he was sent by his uncle to Leipzig to study law; but astronomy wholly engrossed his thoughts, and he employed all his pocket-money in purchas- ing books on that science. Having procured a small cele- stial globe, he used to wait till his tutor went to bed, in order to examine the constellations and learn their names; and when the sky was clear, he spent whole nights in viewing the stars. In 1565, his choleric disposition involved him in a duel with a Danish nobleman, in which he had the mis- fortune to lose part of his nose; yet this defect he so skil- fully supplied by means of gold, silver, and wax, that it was scarcely perceptible. It was about this time that he began to apply to chemistry, proposing nothing less than the dis- covery of the philosopher's stone. In 1571 he returned to Denmark, and was favoured by his maternal uncle Stero Belle with a convenient place at his castle of Herritzvad, near Knudstorp, for making his observations, and building a laboratory. But his marrying a peasant girl occasioned a violent quarrel between him and his relations, and the king was obliged to interpose in order to reconcile them. In 1574, by royal command, he read lectures upon the theory of comets at Copenhagen; and the year following he began his travels through Germany, and proceeded as far as Venice. He then resolved to remove his family, and settle at Basle; but Frederick II., unwilling that Denmark should lose the honour of his residence, bestowed upon him for life the island of Huen in the Sound, to erect an observatory and laboratory there, and conferred on him a pension of two thousand crowns out of the treasury, a fee in Norway, and the canonry of Roschild, which brought him in a thousand more. The first stone of the observatory was laid on the 8th of August 1576. James VI. of Scotland, afterwards James I. of England, on his visit to Denmark to marry the Princess Anne, went to see Tycho Brahe in his retirement at Uranienburg, made him several presents, and wrote a copy of verses in his praise. But soon after the death of King Frederick he was deprived of his pension, fee, and canonry. Finding himself incapable of bearing the expenses of his observatory, he went to Copenhagen, whither he carried some of his instruments, and continued his astro- nomical observations in that city, till by the order of Christi- an IV., he was obliged to discontinue them. He then re- moved his family to Rostock, and afterwards to Holstein, in order to solicit Henry Ranzou to introduce him to the em- peror; and accordingly he was received by Rudolph II. at Prague with the most gratifying marks of respect. That prince gave him a magnificent house till he could procure for him one better fitted for astronomical observations; as- signed him a pension of three thousand crowns; and pro- mised, upon the first opportunity, a fee for him and his de- scendants. But he did not long enjoy his good fortune; for, on the 24th of October 1601, he died of a strangury, in the fifty-fifth year of his age. He was interred in a very magnificent manner in the principal church at Prague, where a noble monument was erected to his memory.

Tycho Brahe, though an accurate observer, and possessed of a powerful understanding, refused to admit the truth of the Copernican system, choosing rather to frame a complicated system of his own, but which, indeed, was adopted by few. The Tychonian system, as it is called, is essentially that of Ptolemy, with certain modifications. This great astronomer was extremely credulous with regard to judicial astrology and presages. If on leaving his house, he met an old woman or a hare upon the road in a journey, he would immediately turn back, persuaded that it was a bad omen. At Uranienburg, he had in his house a madman, whom he placed at his feet at table, and fed with his own hands, superstitiously regarding as prophetic whatever he uttered. Tycho was a man of very violent temper, easily excited to resentment, and though fond of rallying others, was highly provoked if the same liberty were taken with himself. His life has been written by Gassendi. His principal works are:

1. *Prognosticatio Astronomica*, Uranienburg, 1588 and 1589, 2 vols. 4to; 2. *De Mundi Ætheri recentioribus phaenomenis*, 1588, 4to; 3. *Epistolae Astronomicarum libri duo*, Frankfort, 1610, 4to; 4. *Calendarium Naturale Magnum*, 1582; 5. *Oratio de disciplinis Mathematicis*, Copenhagen, 1610, 8vo. His observations were collected by his disciples, and published in 1666 in *Historia Coelestis xx. libris*.

It was the friendship of Tycho which formed Kepler, and directed him in the career of astronomy. The numerous observations of Tycho, of which Kepler found himself the depositary after the death of his master, doubtless contributed greatly to the discovery of those great laws of the system of the world which are known as Kepler's laws, and which, combined with the theory of central forces discovered by Huygens, conducted Newton to the grandest discovery which has ever been made in the sciences, namely, that of universal gravitation.