_In the south and lesser Observatory._ 8. An armillary sphere of brass, with a steel meridian, whose diameter was about 4 cubits. _In the north Observatory._ 9. Brass parallactic rules, which revolved in azimuth above a brass horizon, twelve feet in diameter. 10. A half sextant, of four cubits radius. 11. A steel sextant. 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, shewing every ten seconds. 16. In the museum was the large globe made at Augsburg, see p. 134. _In the Stiern-berg Observatory._ 17. In the central part, a large semicircle, with a brass limb, and three clocks, shewing 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, shewing 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 moveable 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. In almost all the instruments now enumerated, the limb was subdivided by diagonal lines, a method which Tycho first brought into use, but which, in modern times, has been superseded by the inventions of Nonius and Vernier. When Tycho had thus furnished his observatory, he devoted himself to the examination of the stars; and during the twenty-one years which he spent in this delightful occupation, he made vast additions to astronomical science. In order to instruct the young in the art of observation, and educate assistants for his observatory, he had sometimes under his roof from six to twelve pupils, whom he boarded and educated. Some of these were named by the King, and educated at his expense. Others were sent by different academies and cities; and several, who had presented themselves of their own accord, were liberally admitted by the generous astronomer.