“Well,” I said, “from what I can find out, the machine is not designed to screw itself through the air in the direction of its axis, or, by pushing the air downwards, to impart upward motion to the structure, as a screw propeller in water imparts a forward motion to the vessel by pushing the water backwards. The biplane is designed to obtain by a rotary motion the same upward thrust in opposition to the downward pull of gravity as the flapping wings, and the passive outspread wings of birds, and to obtain it by the blades being projected through the air in such a manner as to extract and utilise the practically constant energy of the expansive force of the air.”
“By Jove!” my friend exclaimed, stirring himself in his bed. “That theory is very sound indeed—the soundest I’ve ever heard. Who’s invented it?”
“As I’ve told you, I’ve forgotten,” I replied. “But what does it matter? There are hosts of new inventions every month, and the poor misguided public who put their money into them generally lose it. But I quite agree that the general idea of this is splendid. The war-inventions authorities ought at once to take it up hot and strong. The inventor is, no doubt, an ingenious man of thought and knowledge—whoever he may be. But alas! nobody ever meets with very much encouragement in aeronautics.”
“No,” he said, pillowing his head comfortably. “It is all so mysterious. We take on a wild-cat idea one day and manufacture machines that are declared to work miracles. Then, next week, we abandon the type altogether, and woo some other smooth-tongued inventor.”
“That’s just it,” I laughed. “If the authorities could only adopt some really reliable type to fight Zeppelins. But alas! it seems that they can’t,” I added.
For a few seconds he remained silent. I saw that he was reflecting deeply.
“Well,” he said. “We’ve established listening-posts all round London for its protection.”
“A real benefit they are!” I laughed. “We have officers and men listening all night, it is true. Of course as a picturesque fiction in order to allay public curiosity they publish photographs of men listening to things like gramophone-trumpets.”
“Exactly. The theory of that new invention is extremely sound. That’s my opinion.”
“And mine also,” I said. “I hear that the inventor has told the authorities that if they will assist him to complete his machine—which I expect is a costly affair—he will be able to carry out daily raids on Cuxhaven, Essen, Düsseldorf, and even as far as Berlin; carrying several tons of explosives.”