The very existence of the belief in an extensive southern continent at those early periods presents a twofold cause of doubt. It engendered _at the time_ the supposition that every island to the south of what was previously known, and of which the north part only had been seen, formed a portion of that continent; while _to us_ who, from this distance of time, look back for evidence, the inaccurate representation of such discoveries on maps, especially in or near the longitude of Australia (for longitude could be but laxly noticed in those days) leaves the doubt whether that continent may not have been visited at the period thus represented. Hence, manifestly, it will be requisite to bear well in mind this broadly accepted belief in the existence of a great southern continent, if we would form a right judgment respecting those supposed indications of Australia which are presented on maps of the sixteenth and beginning of the seventeenth centuries. Among the very early writers, the most striking quotation that the editor has lighted upon in connection with the southern continent, is that which occurs in the _Astronomicon_ of Manilius, lib. i, lin. 234 _et seq._, where, after a lengthy dissertation, he says: “Ex quo colligitur terrarum forma rotunda: Hanc circum variæ gentes hominum atque ferarum, Aeriæque colunt volucres. Pars ejus ad arctos Eminet, _Austrinis pars est habitabilis oris, Sub pedibusque jacet nostris_.” The latter clause of this sentence, so strikingly applying to the lands in question, has been quoted as a motto for the title-page of this volume. The date at which Manilius wrote, though not exactly ascertained, is supposed, upon the best conclusions to be drawn from the internal evidence supplied by his poem, to be of the time of Tiberius. Aristotle also, in his _Meteorologica_, lib. ii, cap. 5, has a passage which, though by no means so distinct as the preceding, speaks of two segments of the _habitable_ globe, one towards the north, the other towards the south pole, and which have the form of a drum. Aratus, Strabo, and Geminus have also handed down a similar opinion, that the torrid zone was occupied throughout its length by the ocean, and that the band of sea divided our continent from another, situated, as they suppose, in the southern hemisphere.[3]