hypothesis.  He therefore assumed that the other planets revolved about the sun, while the sun, moon, and stars revolved about the earth as a centre.  Geometrically this is much the same as the Copernican system, but physically it involves the grotesque demand that the whole system of stars revolves round our insignificant little earth every twenty-four hours.  Since his previous small book on the comet, Tycho had evidently considered more fully its possible astrological significance, for he foretold a religious war, giving the date of its commencement, and also the rising of a great Protestant champion.  These predictions were apparently fulfilled almost to the letter by the great religious wars that broke out towards the end of the sixteenth century, and in the person of Gustavus Adolphus.

King Frederick’s death did not at first affect Tycho’s position, for the new king, Christian, was only eleven years old, and for some years the council of regents included two of his supporters.  After their deaths, however, his emoluments began to be cut down on the plea of economy, and as he took very little trouble to carry out any other than scientific duties it was easy enough for his enemies to find fault.  One after another source of income was cut off, but he persevered with his scientific work, including a catalogue of stars.  He had obtained plenty of good observations of 777 stars, but thought his catalogue should contain 1000 stars, so he hastily observed as many more as he could up to the time of his leaving Hveen, though even then he had not completed his programme.  About the time that King Christian reached the age of eighteen, Tycho began to look about for a new patron, and to consider the prospects offered by transferring himself with his instruments and activities to the patronage of the Emperor Rudolph II.  In 1597, when even his pension from the Royal treasury was cut off, he hurriedly packed up his instruments and library, and after a few weeks’ sojourn at Copenhagen, proceeded to Rostock, in Mecklenburg, whence he sent an appeal to King Christian.  It is possible that had he done this before leaving Hveen it might have had more effect, but it can be readily seen from the tone of the king’s unfavourable reply that his departure was regarded as an aggravation of previous shortcomings.  Driven from Rostock by the plague, Tycho settled temporarily at Wandsbeck, in Holstein, but towards the end of 1598 set out to meet the Emperor at Prague.  Once more plague intervened and he spent some time at Dresden, afterwards going to Wittenberg for the winter.  He ultimately reached Prague in June, 1599.  Rudolph granted him a salary of at least 3000 florins, promising also to settle on him the first hereditary estate that should lapse to the Crown.  He offered, moreover, the choice between three castles outside Prague, of which Tycho chose Benatek.  There he set about altering the buildings in readiness for his instruments, for which he sent