MR. HAGEMANN, who is bearing the expense, and Dr. Dreyer, who has undertaken the labour of editing the works of Tycho Brahe, are alike to be congratulated on the appearance of this elegant edition of the first book—the only one ever published—of the “Epistoke Astronomicae.” The frontispiece consists of a handsome portrait of Tycho Brahe, dated 1586, reproduced from the first edition, which appeared in 1596. Here the portrait is enclosed in an arch ornamented with sixteen coats-of-arms, either, we may conjecture, his Sixteen quarterings, or at least the arms of his own and fifteen kindred families. The English reader will note with special interest the arms of Rosenkrans and Guidensteren, and we have not far to seek for bearers of those arms. In Dr. Dreyer's “Tycho Brahe” (1890) Jorgen Rosenkrands is frequently mentioned as a patron of Tycho. He was Governor of Jutland, and in 1588 was made one of the Council of Regency for the young King Christian IV. of Denmark. Axel Guldenstern appears in two letters in the present volume dated 1592, where he is described as a kinsman of Tycho and Governor of Norway. Tychonis Brahe Dani Opera Omnia. Edidit I. L. E. Dreyer. Tomus vi. Pp. v + 375. (Haunkae: Libraria Gyldendaliana, 1919.) Price 19 kr.