through the writings of experienced seamen, and by making use of their statements and explanations; enlarged by many new descriptions and maps. All divided into four books, each volume having its own index. Hereto have been added [besides a course in the art of navigation] new tables of the declination of the sun, derived from the observations of Tycho Brahe, and calculated from the meridian of Amsterdam. Also new tables and instructions in the right use of the Pole Star and other Stars, for the benefit of all navigators.” In 1627 the Dutch edition seems to have been issued by “Jan Janssoon wonende op ’t water,” the first part being dated 1626, and the second part dated 1625. In the dedication of his third volume to the States General and to Prince Maurice, a dedication dated September 1, 1618, there is to be found a statement by Blaeu which shows his own opinion of the importance of the first two volumes. He writes he is “assured without boasting that this third volume will be as useful as the two preceding, containing the description of Eastern and Western Navigation, of which Your Honorable Body [States General] and Your Excellency [Maurice] at other times have had sufficient proof from trustworthy certificates of well known navigators, and also from the statements of the famous pilot Lucas Waghenaer.” To have from Lucas Jansz. Waghenaer a favorable criticism concerning a work which was destined to be considered superior to his own, is of no little importance. Blaeu further acknowledges in his introduction the influence of Willem Barentszoen’s maps upon his own, for he states “to the kind reader” that “we have for some years past collected very carefully all observations and plans, by means of which we have improved and enlarged in many respects the descriptions of Willem Barentsz., whose writings have been of much value to us in this work. Besides, we have added the descriptions of all the sea-coasts in the east which were not laid down by him, as of the islands of Candia, Cyprus, the coasts of Syria and Egypt, and also of the Greek islands; and how one in this way can sail even to Constantinople; and we have put this all together.” “The uses of this Book” he sets forth in six brief introductory chapters, in which he treats of “1--The difference between the Dutch and the Italian marine maps; 2--Why the compass needle is not laid directly under the compass lily; 3--Why the marine charts of the Mediterranean Sea are not drawn showing the degrees of latitude; 4--How to reckon latitude; 5--How the declination of the compass needle or the variation of the compass may be determined; 6--How to find the elevation of the sun from its shadow.”