The car of the underground railway carried me swiftly to the place where the motionless, beautiful body of the Integral , not yet spiritualized by fire, was glittering in the docks in the sunshine. With closed eyes I dreamed in formulae. Again I calculated in my mind what was the initial velocity required to tear away the Integral from the earth. Every second the mass of the Integral would change because of the expenditure of the explosive fuel. The equation was very complex with transcendant figures. As in a dream I felt, right here in the firm calculated world, how someone sat down at my side, barely touching me and saying, “Pardon.” I opened my eyes. At first, apparently because of an association with the Integral , I saw something impetuously flying into the distance: a head; I saw pink wing-ears sticking out on the sides of it, then the curve of the overhanging back of the head, the double-curved letter S.