This remarkable body presents to us one of the most interesting phenomena in astronomy. The date of its first appearance has not been exactly ascertained. Tycho saw it on the 11th November, but Cornelius Gemma had seen it on the 9th, Paul Hainzel saw it on the 7th of August at Augsburg, and Wolfgangus Schulerus observed it at Wittenberg on the 6th. Tycho conjectures that it was first seen on the 5th, and Hieronymus Munosius asserts that at Valentia, in Spain, it was not seen on the 2d, when he was shewing that part of the heavens to his pupils. This singular body continued to be seen during 16 months, and did not disappear till March 1574. In its appearance it was exactly like a star, having none of the distinctive marks of a comet. It twinkled strongly, and grew larger than _Lyra_ or _Sirius_, or any other fixed star. It seemed to be somewhat larger than _Jupiter_, when he is nearest the earth, and rivalled _Venus_ in her greatest brightness. In the _first_ month of its appearance it was less than Jupiter; in the _second_ it equalled him; in the _third_ it surpassed him in splendour; in the _fourth_ it was equal to _Sirius_; in the _fifth_ to _Lyra_; in the _sixth_ and _seventh_ to stars of the _second_ magnitude; in the _eighth_, _ninth_, and _tenth_, to stars of the _third_ magnitude; in the _eleventh_, _twelfth_, and _thirteenth_, to stars of the _fourth_ magnitude; in the _fourteenth_ and _fifteenth_ to stars of the _fifth_ magnitude; and in the _sixteenth_ month to stars of the _sixth_ magnitude. After this it became so small that it at last disappeared. Its colour changed also with its size. At first it was white and bright; in the third month it began to become yellowish; in the fifth it became reddish like Aldebaran; and in the seventh and eighth it became bluish like Saturn; growing afterwards duller and duller. Its place in the heavens was invariable. Its longitude was in the 6th degree and 54th minute of Taurus; and its latitude 53 deg. 45' north. Its right ascension was 0 deg. 26-2/5' and its declination 61 deg. 46-3/4'. It had no parallax, and was unquestionably situated in the region of the fixed stars. After Tycho had published his book, he proposed to travel into Germany and Italy, but he was seized with a fever, and he had no sooner recovered from it, than he became involved in a love affair, which frustrated all his schemes. Although Tycho was afraid of casting a stain upon his nobility by publishing his observations on the new star, yet he did not scruple to debase his lineage by marrying a peasant girl of the village of Knudstorp. This event took place in 1573, and in 1574 his wife gave birth to his daughter Magdalene. Tycho's noble relations were deeply offended at this imprudent step; and so far did the mutual animosity of the parties extend, that the King himself was obliged to effect a reconciliation.