THE ZENI MAP.
[2nd part]
[THE ZENI MAP. (complete view)]

The year 1569 is marked by a stride in cartographical science, of which we have not yet outgrown the necessity.

THE WARSAW CODEX, 1467; after Nordenskiöld.
[1st part]
[THE WARSAW CODEX, 1467; after Nordenskiöld. (complete view)]

1569. Mercator's projection.

The plotting of courses and distances, as practiced by the early explorers, was subject to all the errors which necessarily accompany the lack of well-established principles, in representing the curved surface of the globe on a plane chart. Cumbrous and rude globes were made to do duty as best they could; but they were ill adapted to use at sea. Nordenskiöld (Facsimile Atlas, p. 22) has pointed out that Pirckheimer, in the Ptolemy of 1525, had seemingly anticipated the theory which Mercator now with some sort of prevision developed into a principle, which was applied in his great plane chart of 1569. The principle, however, was not definite enough in his mind for the clear exposition of formulæ, and he seems not to have attempted to do more than rough-hew the idea. The hint was a good one, and it was left for the Englishman Edward Wright to put its principles into a formulated problem in 1599, a century and more after Columbus had dared to track the ocean by following latitudinal lines in the simplest manner.