We must therefore fancy to ourselves a parallelogram, and within it a chlamys-shaped figure, described in such a manner that the length of the one figure may correspond to the length and size of the other, and likewise breadth to breadth. The habitable earth will therefore be represented by this kind of chlamys. We have before said that its breadth is marked out by parallels bounding its sides, and separating on either side the portions that are habitable from those that are not. On the north [these parallels] pass over Ierna,[743] and on the side of the torrid zone over the Cinnamon Country. These lines being produced east and west to the opposite extremities of the habitable earth, form, when joined by the perpendiculars falling from their extremities, a kind of parallelogram. That within this the habitable earth is contained is evident, since neither its greatest breadth nor length project beyond. That in configuration it resembles a chlamys is also clear, from the fact that at either end of its length, the extremities taper to a point.[744] Owing to the encroachments of the sea, it also loses something in breadth. This we know from those who have sailed round its eastern and western points. They inform us that the island called Taprobana[745] is much to the south of India, but that it is nevertheless inhabited, and is situated opposite to the island of the Egyptians and the Cinnamon Country, as the temperature of their atmospheres is similar. On the other side the country about the embouchure of the Hyrcanian Sea[746] is farther north than the farthest Scythians who dwell beyond India, and Ierna still more so. It is likewise stated of the country beyond the Pillars of Hercules, that the most western point of the habitable earth is the promontory of the Iberians named the Sacred Promontory.[747] It lies nearly in a line with Gades, the Pillars of Hercules, the Strait of Sicily, and Rhodes;[748] for they say that the horologes accord, as also the periodical winds, and the duration of the longest nights and days, which consist of fourteen and a half equinoctial hours. From the coast of Gades and Iberia ... is said to have been formerly observed.[749] Posidonius relates, that from the top of a high house in a town about 400 stadia distant from the places mentioned, he perceived a star which he believed to be Canopus, both in consequence of the testimony of those who having proceeded a little to the south of Iberia affirmed that they could perceive it, and also of the tradition preserved at Cnidus; for the observatory of Eudoxus, from whence he is reported to have viewed Canopus, is not much higher than these houses; and Cnidus is under the same parallel as Rhodes, which is likewise that of Gades and its sea-coast.