When we turn to the Phædrus, we find that, in its highly poetical description, the rotation of the heaven occupies a prominent place. The internal circumference of the heavenly sphere, as well as its external circumference or back ([Greek: nô=ton]), are mentioned; also its periodical rotations, during which the gods are carried round on the back of the heaven, and contemplate the eternal Ideas occupying the super-celestial space (p. 247, 248), or the plain of truth.[5] But the purpose of this poetical representation appears to be metaphysical and intellectual, to illustrate the antithesis presented by the world of Ideas and Truth on one side--against that of sense and appearances on the other. Astronomically and cosmically considered, no intelligible meaning is conveyed. Nor can we even determine whether the rotations of the heaven, alluded to in the Phædrus, are intended to be diurnal or not; I incline to believe not ([Greek: me/chri tê=s _e(te/ras_ perio/dou]--p. 248--which can hardly be understood of so short a time as one day). Lastly, nothing is said in the Phædrus about the cosmical axis; and it is upon this that the rotations of the earth intimated in the Timæus depend. [Footnote 5: Whether [Greek: E)sti/a] in the Phædrus, which is said "to remain alone stationary in the house of the Gods," can be held to mean the Earth, is considered by Proklus to be uncertain (p. 681).] Among the different illustrations, given by Plato in his different dialogues respecting the terrestrial and celestial bodies, I select the tenth book of the Republic as that which is most suitable for comparison with the Timæus, because it is only therein that we learn how Plato conceived the axis of the kosmos. M. Boeckh (Untersuchungen, p. 86) wishes us to regard the difference between the view taken in the Phædon, and that in the Republic, as no way important; he affirms that the adamantine spindle in the Republic is altogether mythical or poetical, and that Plato conceives the axis as not being material. On this point I dissent from M. Boeckh. The mythical illustrations in the tenth book of the Republic appear to me quite unsuitable to the theory of an imaginary, stationary, and immaterial axis. Here I much more agree with Gruppe (p. 15, 26-29), who recognises the solid material axis as an essential feature of the cosmical theory in the Republic; and recognises also the marked difference between that theory and what we read in the Phædon. Yet, though Gruppe is aware of this important difference between the Republic and the Phædon, he still wishes to illustrate the Timæus by the latter and not by the former. He affirms that the earth in the Timæus is conceived as unattached, and freely suspended, the same as in the Phædon; but that in the Timæus it is conceived, besides, as revolving on its own axis, which we do not find in the Phædon (p. 28, 29). Here I think Gruppe is mistaken. In construing the words of Timæus, [Greek: ei(lome/nên (i)llome/nên) peri\ to\n dia\