'Here was the new view. Plainly, this second species of Man was subterranean. There were three circumstances in particular which made me think that its rare emergence above ground was the outcome of a long-continued underground habit. In the first place, there was the bleached look common in most animals that live largely in the dark--the white fish of the Kentucky caves, for instance. Then, those large eyes, with that capacity for reflecting light, are common features of nocturnal things--witness the owl and the cat. And last of all, that evident confusion in the sunshine, that hasty yet fumbling awkward flight towards dark shadow, and that peculiar carriage of the head while in the light--all reinforced the theory of an extreme sensitiveness of the retina.

'Beneath my feet, then, the earth must be tunnelled enormously, and these tunnellings were the habitat of the new race. The presence of ventilating shafts and wells along the hill slopes--everywhere, in fact, except along the river valley--showed how universal were its ramifications. What so natural, then, as to assume that it was in this artificial Underworld that such work as was necessary to the comfort of the daylight race was done? The notion was so plausible that I at once accepted it, and went on to assume the _how_ of this splitting of the human species. I dare say you will anticipate the shape of my theory; though, for myself, I very soon felt that it fell far short of the truth.

'At first, proceeding from the problems of our own age, it seemed clear as daylight to me that the gradual widening of the present merely temporary and social difference between the Capitalist and the Labourer, was the key to the whole position. No doubt it will seem grotesque enough to you--and wildly incredible!--and yet even now there are existing circumstances to point that way. There is a tendency to utilize underground space for the less ornamental purposes of civilization; there is the Metropolitan Railway in London, for instance, there are new electric railways, there are subways, there are underground workrooms and restaurants, and they increase and multiply. Evidently, I thought, this tendency had increased till Industry had gradually lost its birthright in the sky. I mean that it had gone deeper and deeper into larger and ever larger underground factories, spending a still-increasing amount of its time therein, till, in the end--! Even now, does not an East-end worker live in such artificial conditions as practically to be cut off from the natural surface of the earth?