which Baron Nordenskiöld has written as follows to Sir Clements Markham:—
CROSS-STAFF.
(From Davis's 'Seaman's Secrets', London, 1594.)
"The globe of Behaim is, without comparison, the most important geographical document that appeared between a.d. 150, the date of the composition of Ptolemy's Atlas, and a.d. 1507, when Ruysch's map of the world was published. This globe is not only the oldest known to exist, but, from its size and its wealth of geographical detail, it far surpassed all analogous monuments de géographie, until the appearance of the globe of Mercator. It is the first geographical document which, without any reserve, adopts the existence of antipodes. It is the first which plainly shows the possibility of a passage by sea to India and Cathay. It is the first on which the discoveries of Marco Polo are clearly indicated. It is true that the Behaim globe may be said to have been preceded, in some respects, by some other earlier maps of the fifteenth century—for instance, the map in a codex of Pomponius Mela of 1427, in the library of Rheims, and that of Fra Mauro. But if these are impartially studied, it will be found that they are based on the idea of Homer, that the earth is a large circular island encompassed by the ocean, a conception totally incompatible with the new geographical discoveries of the Spaniards. These and analogous maps are, therefore, not in the slightest degree comparable with the globe of Behaim, which may be said to be an exact representation of the geographical knowledge of the period immediately preceding the first voyage of Columbus."
The ascertaining of the longitude continued for many generations to be a difficulty, although Werner of Nürnberg proposed the method of observing the distance of the moon from the sun with simultaneous altitudes—a method subsequently known as taking a "lunar"; and Gemma Frisius of Louvain had an idea, made public in 1530, that longitude might be found by comparison of times kept by small clocks, a foreshadowing of the modern use of the chronometer.
Columbus was the first to observe the variation of the needle. This was on September 14th, 1492. It afterwards attracted the attention of Sebastian Cabot. But the peculiarity was very generally believed at the time to be non-existent, the observations being inaccurate; and, as late as 1571, Sarmiento doubted it.
Globes, and not charts, were chiefly used by the early sixteenth--
