In the early charts and in the old tables of situations, many Islands are marked of which no other notices have come before the public. Most of these are omitted in the charts now in use, being excluded by later discoveries; and some are still retained. They possess nearly alike a kind of traditional authority; and some of them a possibility, nothing to the contrary being known, of being met with at a future period. It is therefore endeavoured here to collect them into one list.

Among the hydrographic authorities for early Discoveries in the South Sea, the one which has been most generally consulted is the Spanish chart published with the History of Commodore Anson's Voyage, in which the track of the Manila galeon is described; it being more generally known than any other early chart of the Pacific Ocean, in consequence of its being so published. On applying to it, and making the necessary examination, an extraordinary variation is found in it from other charts and from the tables then in use.

The original from which the chart in Anson was published, was a manuscript chart drawn for the use of the Spanish General of the Galeons, and, it is said, contained all the Discoveries which had at any time been made in the navigation between the Philippine Islands and New Spain.