[NUMBER 22] [NUMBER 21] [NUMBER 23] 21 ASTRONOMIC ASTROLABE OF BRASS AND SILVER, BY JOHANN WILLEBRANDT AUGSBURG, 16TH CENTURY Circular, with pediment for suspension. Movable silver disk gives the means of establishing the hours and longitudes of important places. The hour is fixed by the sight of the polar star through the orifice in the centre. On the other side a silver disk with dentilled edges marks the days of the month. Latin inscriptions explain the use of the instrument. Signed by the maker on handle. Diameter without handle, 31/2 inches Described in « La Collection Spitzer », Paris, 1892, vol. 5, p. 84, No. 18. SALE, PARIS, 1893, CATALOGUE NUMBER 2777. [SEE ILLUSTRATION] 6