"That fellow Lindemann is a _Dummer Teufel_," said von Herrnung, shrugging. "My German landlord.... Why—do you know him?" asked Sherbrand with a look of surprise. "No, certainly. But you—you said the fellow’s name was Lindemann. Not so? No?—then I am mistaken," said von Herrnung with another shrug. He hurried on as though to cover a mistake with a spate of sentences: "Of course, with Rathenau and Wolff I have nothing to do. Save as an old customer, of whom they have asked a favour—you understand? Indeed I—you will pardon me!—do not your hoverer regard as an original invention. In 1912 our German Ministry of Marine completed a gun-boat fitted with a gyroscopic stabiliser to prevent rolling—you understand—in stormy weather. The device was hellishly effective." "So effective," rejoined Sherbrand, without the quiver of a facial muscle, though there was laughter in his eyes, "that it broke up the ship." "_Es mag wohl sein!_" returned von Herrnung, covering discomfiture, if he felt it, with his imperturbable shrug and hard blue stare. Sherbrand went on, straightening his wide shoulders and clasping his hands loosely at his back as he talked: "I don’t claim that my patent is an absolutely new invention. Far from it. But it is a new arrangement of some old ideas, and limited though its use may be—it works. You have seen it working. You agree that it justifies its name?" He waited for the assent, and went on: "Possibly if I had described it as an aërial drag-anchor, I should have explained its uses more clearly. It is no good at all when your machine isn’t flying level—of course you understand that? If you were ass enough to try to dive without cutting out the power that drives the horizontal screws you would drop to the ground like a plummet and break into a million of little bits—or dig a hole in the earth big enough for a Tube Station. But—keeping an even line of flight—when you switch it on it pulls against the tractor just sufficiently to give you—not immovability—but poise. Sufficient to take a photograph or drop an explosive with a good deal of accuracy." The small boy lying outstretched on the warm turf near them, thought dolefully: "_Dummer Teufel_ meant ’stupid devil’ in German. But this talk is dreadfully business, I can’t stow away much. Man alive! I wish Roddy Wrynche or some other fellow with a top-hole memory had got this job to tackle. And yet the Chief trusted it to _me_!" All this, while Sherbrand was explaining. "M. Jourdain declared himself completely satisfied. His observer said that I maintained poise and stability for five minutes longer than the stipulated twenty-five. He looked at the altimeter and said I should receive a definite answer within a couple of days.... Unlucky brute! Someone must have run over him!"