I was startled when I got back to find the dome complete again and preparation being made for constructing some other irelium shell. The fence-work had been raised. By its wall stood the key-board of a gigantic organ-like musical instrument, the other half of which was so arranged within the new framework that the whole volume of its sound should bear upon whatever the fence enclosed. A huge bell mouth opened out into the chamber; and I soon saw that out of this issued a snow-storm of irelium particles which floated lightly in the air. A peal of music rang out from the instrument, and I saw the dust motes settle rapidly into a symmetrical figure, that minute by minute grew into a gigantic nautilus shell. The musician who sat at the key-board watched the snow-whirl within and the magical rise of the walls. I perceived that the bar of music was repeated again and again, with gradual ingrafting of variation as the shell-like walls bent over. At a certain point where the whorl began to incurve backwards the strain completely changed and reminded me of a fugue. Back and forth it shot its monotonous shuttle of sound. I was spellbound by the cradling melody and the sinuous flexure of the vast conch. The completion of the process and the cessation of the music broke the spell, and I pressed near to ask explanations and to see the result. Some enchanter’s power must surely have drawn in the floating particles to the thin curves of the structure and held them there; for the motes continued to float unattracted, but in sparse and sparser cloud; and at last they ceased to move, and settled on the fence, dimming its translucence. I felt the metal floor grow first hotter and hotter, and then cooler and cooler till it was ice-cold. Within a fraction of an hour the whole process was complete; the fencing walls were shaken to dust, and there stood the gigantic nautilus perfect in its grace, clear as crystal but for the frostwork of nautilus patterns all over its surface. It was a new experiment in form for a winged ship of the air, and as I stood the wings were added and the engines put on board. The navigators embarked; a smaller quadrant of the dome crashed aside; and out by the aperture floated this huge air-bubble rainbow-lustrous in the sun.