He expected an answer, but Dicky failed to give it. Gasps of astonishment escaped his wide-parted lips, gasps denoting pleasure and admiration. For up above, now that he had shielded his eyes from the glare and looked away from the light, he could dimly make out huge girders stretching from left to right, criss-crossing and interlacing with one another. Here and there they ended apparently in nothing. Elsewhere they could be traced to their junction with other girders. And on beyond them, far overhead, he could even see stars, blurred a trifle by the material through which he observed them. "Well, of all the wonderful things of which I have ever heard, this beats all!" he gasped at last. "What's the thing made of? There are girders above there heavy enough to carry a 'Dreadnought'. There's a huge framework that looks as if it were constructed of solid bars of steel; and yet, to look at them in a half light, which just throws out their outline, one realizes that they are made of something else, something transparent--yes, that's the term--for when one stares direct at the light, knowing full well that there are more girders in that direction, none of them can be detected. George, this beats everything! What's the meaning of it all?" "The meaning of it all! Why, that Joe Gresson is about the smartest fellow you ever heard of, that he's had the courage to employ a substance for the framework, and almost every part of this ship, which the average engineer would treat with scorn. In short, he's the discoverer of a substance which he calls celludine, which isn't celluloid, nor common glass, nor talc, and yet which is wonderfully like all three substances. You'll hear more about it, my boy. You'll get the same idea of Joe that I and all the others have. Look here! Just rap your knuckles against the wall of the saloon." Dicky did as he was bidden, though he was still so astonished at the news given him that he did not even trouble to ask the reason. "Well, how does it feel? Of course, there's a silk covering. Under that is the celludine. There's the same stuff here under the carpet." "Hard, and yet it gives," said Dicky. "Appears to be very thin, and yet, I imagine, is very strong." "That's celludine," cried Alec triumphantly. "Every wall, every door and frame is composed of it. Only here, where there are cabins--and one doesn't want to be stared at all day long--it's coloured a milky white, and so isn't transparent. But the ceiling is, that's why you can look aloft and see the stars floating overhead. But come along. We'll take a breather. I'll lead you to a spot that'll raise your hair, but will give you a better idea of this airship than you can possibly have imagined." They left the saloon at once, and passing along the gallery paused to look into a room on the far side. There they found Commander Jackson, Andrew, and Joe comfortably seated, smoking and chatting quietly. "Ah, comfortably dressed and fed, my lad?" sang out the Commander.