How well the picture of that grouping has bitten into my brain; the back of Cavor’s downcast head just in front of me, and the dejected droop of his shoulders, and our guide’s gaping visage, perpetually jerking about him, and the goad-bearers on either side, watchful, yet open-mouthed⁠—a blue monochrome. And, after all, I do remember one other thing besides the purely personal affair, which is, that a sort of gutter came presently across the floor of the cavern, and then ran along by the side of the path of rock we followed. And it was full of that same bright blue luminous stuff that flowed out of the great machine. I walked close beside it, and I can testify it radiated not a particle of heat. It was brightly shining, and yet it was neither warmer nor colder than anything else in the cavern.