gymnasmata), in which the catalogue of 777 stars occurred, was still unfinished, he thought it desirable to distribute a limited number of manuscript copies of his catalogue of stars. It was probably for this purpose only that he had before leaving Hveen got a number of stars hastily observed in order to exhibit the places of a thousand stars, and not be inferior to Ptolemy with his 1028 stars. This catalogue of longitudes and latitudes of 1000 stars for the year 1600 was now neatly copied on paper or parchment by his assistants, and to it were added tables of refraction and precession, of the right ascension, and declination of a hundred stars for the epoch 1600 and 1700, and a catalogue of longitude, latitude, right ascension, and declination of thirty-six stars according to Alphonso, Copernicus, and himself, for the sake of comparison.[1] The lengthy introduction to this manuscript work was in the form of a dedication to the Emperor Rudolph II., dated the 2nd January 1598.[2] In this Tycho reviews the successive star-catalogues of Hipparchus and his successors down to and including "incomparabilis vir Nicolaus Copernicus," and he remarks that in reality nobody after Hipparchus has observed any great number of stars, but that Ptolemy, Albattani, Alphonso, and Copernicus had merely added precession to the longitudes, which circumstance in connexion with the limited accuracy of the catalogue of Hipparchus, and the numerous great errors which had crept into it, made it desirable to have a new star-catalogue prepared, in which the positions of the stars were given with the greatest accuracy now attainable. This Tycho had done, and offered it as a New Year's gift to the Emperor. The catalogue and the printed book, Mechanica, were sent to the Emperor by the hands of Tycho's eldest son, who also was the bearer of a
