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setting forth the merits of each. While that under Tycho's picture leaves posterity to judge his work, the lines under the picture of his hoped-for descendant are less modest, expressing the hope that the latter might be worthy of his great ancestor. Tycho was represented as pointing up to his system of the world, while his other hand held a slip of paper with the query, "Quid si sic?"

In the centre of each crypt was a large instrument, the floor rising gradually by circular stone steps up to the walls.^[1] The instruments were an azimuthal quadrant (quadrans volubilis) of 51/2 feet radius, with an azimuth circle at the top of the wall (Mechanica, fol. B. 2), a zodiacal armillary sphere (C. 4), a large quadrant of brass (radius 7 feet) enclosed in a square of steel, and likewise furnished with an azimuth circle on the wall (B. 4); a sextant of 51/2 feet radius for measuring distances (D. 5), and in the largest southern crypt a large equatorial instrument, consisting of a declination circle of 91/2 feet diameter, revolving round a polar axis, and a semicircle of 12 feet diameter, supported on stone piers, and representing the northern half of the Equator (D. 2). In addition to these fixed instruments, there were various smaller portable ones kept at Stjerneborg, which could be mounted on the pillars and stands outside or held in the hand; namely, a portable armilla 4 feet in diameter,^[2] a triquetrum, a small astrolabium or planisphere, the small quadrant described above, and two small instruments made by Gemma Frisius, namely, a cross-staff and a circle (annulus astronomicus), both of brass. With the exception of these two and the triquetrum of Copernicus, all the instruments in Tycho's possession were made in his

1. The number of steps in each crypt may be seen on the plan above. The floor of the crypt G (where the sextant was placed) was flat.
2. This was placed either at H or at I, and served to measure declinations of stars near the horizon which could not be got at with the subterranean instruments. See Epist. Astron., p. 229.