We can, however, see no necessity why he should for ever continue to do so. Widely different conditions seem to prevail near the centre and out towards the circumference of the sidereal world. What may be designated the interior vacuity of the Milky Way is occupied mainly by stars of the solar type, including one to our apprehension super-eminent over the rest; they are separated by vast, apparently clear intervals; they are non-nebulous, and of stable constitution. This secure habitat is ours for the present, although it may at some future time be exchanged for one less exempt from disturbance. The shape and size of the sun's orbit are utterly unknown; the changes of environment, accordingly, that will accompany the description of it defy conjecture. Our actual course is inclined at a small angle to the plane of the Milky Way. It will presumably become deflected, but perhaps not sufficiently to keep our system clear of entanglement with the galactic star-throngs. In our ignorance of their composition no forecast of the results can be attempted: they are uncertain and exorbitantly remote. Moreover, the comparative slowness of the sun's motion in a manner guarantees the permanence of his subsisting cosmical relations. For anything that science can tell, they may ultimately be subverted by some preordained catastrophe; but the possibility lies outside the sphere of rational forecast. The universe, as reflected in the mind of man, gains extent as the mirror acquires polish. Early astronomers conceived of but one solar system and one 'dædal earth,' upon which the 'pale populace of heaven' rained influences sinister or propitious. Later, human egotism took another form. The whole universe was assimilated to our particular little settlement in it. Terrestrial conditions were universalized. None divergent from them were counted admissible or profitable. But one answer seemed possible to the perpetual _Cui bono?_ with which restless thought assailed the heavens. But one purpose was regarded as worthy of fulfilment, that of multiplying, in distant sidereal climes, copies of our own planet, and of providing suitable locations for myriads of intellectual beings, as little alien to ourselves as might be compatible with the minimum of diversity in their material surroundings. The spread of this astral philanthropy has been in some measure checked by the advance of knowledge. Our position and circumstances have been shown by it to be, if not quite peculiar, at any rate very far from inevitable. It has reduced, by a process of exclusions, to a relatively limited number the class of stars that can fairly be regarded as possible centres of vitality; it has immensely widened the scope of discernible variety in cosmical arrangements, and held out warnings against errors of exposition due to inborn prejudices. And we shall surely not wander from the truth by recognising our inability to penetrate all the depths and complexities of Infinite Design. FOOTNOTES: