12. Another half sextant with steel limb, four cubits radius. 13. The parallactic rules of Copernicus. 14. Equatorial armillaries. 15. A quadrant of a solid plate of brass, five cubits in radius, showing every ten seconds. 16. In the museum was the large globe made at Augsburg. _In the Sternberg Observatory._ 17. In the central part, a large semicircle, with a brass limb, and three clocks, showing hours, minutes, and seconds. 18. Equatorial armillaries of seven cubits, with semi-armillaries of nine cubits. 19. A sextant of four cubits radius. 20. A geometrical square of iron, with an intercepted quadrant of five cubits, and divided into fifteen seconds. 21. A quadrant of four cubits radius, showing ten seconds, with an azimuth circle. 22. Zodiacal armillaries of brass, with steel meridians, three cubits in diameter. 23. A sextant of brass, kept together by screws, and capable of being taken to pieces for travelling with. Its radius was four cubits. 24. A movable armillary sphere, three cubits in diameter. 25. A quadrant of solid brass, one cubit radius, and divided into minutes by Nonian circles. 26. An astronomical radius of solid brass, three cubits long. 27. An astronomical ring of brass, a cubit in diameter. 28. A small brass astrolabe. Tycho Brahe carried on his work at Uraniberg for twenty-one years, and appears to have been visited by many of the princes of the period and by students anxious to learn from so great a man. In Frederick’s treatment of Tycho Brahe we have an early and munificent and, in its results, most successful instance of the endowment of research. On the death of Frederick II., in 1588, Christian IV. came to the throne. The successor cared little for astronomy, and his courtiers, who were jealous of Tycho’s position, so acted upon him that the pension, estate and canonry with which Tycho had been endowed were taken away. Unable to put up with these insults and loss of his money, he left for Wandesburg in 1597, where he was entertained by Count Henry Rantzau. It was now that he wrote and published the _Astronomiæ instauratæ Mechanica_, a copy of which, together with his catalogue of 1000 stars, was sent to the Emperor Rudolph II., who invited him to go to Prague. This he accepted, and he and his family went to the castle of Benach in 1599, and a pension of 3000 crowns was given to him. Ten years afterwards he removed with his instruments into Prague to a house purchased and presented to him by the Emperor; here he died in the same year. The wonderful assistance which Tycho Brahe was able to bring to astronomy shows that then, as now, any considerable advance in physical investigation was more or less a matter of money, and whether that money be found by individuals or corporations, now or then, we cannot expect any considerable advance without such a necessary adjunct. [Illustration: