"X = - 4 {C^2} {x^3}," murmured Stobalt abstractedly. "I assure you," he explained, leaving the higher mathematics at her reproach, "that I had quite satisfied myself that you were not.... It all turns on the extra tension thrown on the crank by the additional three feathers. I am convinced that English makers have gone as far as they safely can in that direction." He glanced at her wings as he mused. They were of the familiar detached feather—or "venetian blind," as it was commonly called—pattern, and wonderfully graceful in their long sweep and elegant poise. Made of the purest white celluloid, just tinted with a delicate and deepening pink at the base, they harmonised with her sea-green costume as faultlessly as the lily with the leaves it springs from. Stobalt himself used the more difficult but much more powerful "bat" shape, built up of gold-beaters' skin; he had already folded them in rest, but in those early days the prudish conventions of the air debarred the girl from seeking a like repose.
"I should certainly discard the three outside feathers," he summed up.
"I shall certainly discard the whole thing," she replied. "I do not know which felt the worse—being killed or being saved."
He made a gesture that would seem to say that the personal details of the adventure were better dismissed. He was plainly a man of few words, but the mechanical defect still held his interest.
"One understands that a brave man always dislikes being thanked," she continued a little nervously; "and, indeed, what can I say to thank you? You have saved my life, and I know that it must have been at a tremendous risk to yourself."
"I think," he said, "that the sooner you forget the incident.... That and the removal of those three feathers." His gestures were deliberate and the reverse of vivacious, but when he glanced up and moved a hand, it at once conveyed to the girl that in his opinion nothing else need stand in the way of her recovered powers and confidence.
"And there is," she said timidly, "nothing?" Precisely what there might be had not occurred to her satisfactorily.
"Nothing," he said, without the air of being heroic in his generosity. "Unless," he added, "you care to promise that you will not let——" He stopped with easy self-possession and turned enquiringly to a man in some official dress who had suddenly appeared in the glade.
"Have you a licence?" demanded the official, ignoring Stobalt and addressing himself in a style that at one time would have been deemed objectionably abrupt, to the lady. He was in point of fact a policeman, and from a thong on his wrist swung a truncheon, while the butt of a revolver showed at his belt. He wore no number or identifying mark, for it had long since been agreed that it must be objectionable to their finer feelings to treat policemen as though they were—one cannot say convicts, for a sympathetic Home Secretary had already discontinued the numbering of convicts on the ground that it created a state of things "undistinguishable from slavery," though not really slavery—but as though they were railway bridges or district council lamp-posts. "Treat a man as a dog, and he becomes a dog," had been the invincible argument of the band of humanitarians who had introduced what was known as the "Get-up-when-you-like-and-have-what-you-want" system of prison discipline, and "Treat a man as a lamp-post, and he becomes a lamp-post," had been the logical standpoint of the Amalgamated Union of Policemen and Plain Clothes Detectives.
"Yes," replied the girl, and her voice had not quite that agreeable intonation that members of the force usually hear from the lips of fair young ladies nowadays. "Do you wish to see it?"