Upon these reasons alone I should dissent from M. Cousin's sixth argument. But I have other reasons besides. He rests it upon the two allegations that the doctrine of the earth's motion was the subject of much controversial debate in Plato's time, and of great importance in itself. Now the first of these two allegations can hardly be proved, as to the time of Plato; for Aristotle, when he is maintaining the earth's immobility, does not specify any other opponents than the Pythagoreians and the followers of the Platonic Timæus. And the second allegation I believe to be unfounded, speaking with reference to the Platonic Timæus. In the cosmical system therein embodied, the rotation of the earth round the cosmical axis, though a real part of the system, was in itself a fact of no importance, and determining no results. The capital fact of the system was the position and function of the earth, packed close round the centre of the cosmical axis, and regulating the revolutions of that axis. Plato had no motive to bring prominently forward the circumstance that the earth revolved itself along with the cosmical axis, which circumstance was only an incidental accompaniment. I have thus examined all the arguments adduced by M. Cousin, and have endeavoured to show that they fail in establishing his conclusion. There is, however, one point of the controversy in which I concur with him more than with Boeckh and Martin. This point is the proper conception of what Plato means by the _cosmical axis_. Boeckh and Martin seem to assume this upon the analogy of what is now spoken of as the axis of the earth: M. Boeckh (p. 13) declares the axis of the kosmos to be a prolongation of that axis. But it appears to me (and M. Cousin's language indicates the same) that Plato's conception was something very different. The axis of the earth (what astronomers speak of as such) is an imaginary line traversing the centre of the earth; a line round which the earth revolves. Now the cosmical axis, as Plato conceives it, is a solid material cylinder, which not only itself revolves, but causes by this revolution the revolution of the exterior circumference of the kosmos. This is a conception entirely different from that which we mean when we speak of the axis of the earth. It is, however, a conception symbolically enunciated in the tenth book of the Republic, where the spindle of Necessity is said to be composed of adamant, hard and solid material, and to cause by its own rotation the rotation of all the _verticilli_ packed and fastened around it. What is thus enunciated in the Republic is implied in the Timæus. For when we read therein that the earth is packed or fastened round the cosmical axis, how can we understand it to be packed or fastened round an imaginary line? I will add that the very same meaning is brought out in the translation of Cicero--"_trajecto axe sustinetur_" (terra). The axis, round which the earth is