Air Currents which Keep Birds Afloat without Effort What is the mysterious secret of the impalpable energy that soaring birds extract from the air, which enables them not merely to maintain themselws in flight with wings motionless, but to move forward in any direction?
Aerial scientists of world repute, such as Professor Nimfubr, of Austria, and Herr Rumpler, of Germany, have since the war—with all the resources of marvellous instruments and laboratories at their command—been investigating this problem anew.
Now tidings reach air circles in Great Britain that Herr Rumpler, completing the main stage of a definitive research, has come to a conclusion which is considered by experts to be extraordinarily important.
His meticulous investigation, of which vague reports have been current from time to time, has, it is known, been concerned with the' very structure of moving air.
He has satisfied himself that when a volume of air is in motion in the form, say, of a gust, it is internally in a state of rapid, constant, and powerful vibration. Herr Rumpler has, it fs said, actually measured these vibrations or swiftly successive '"'energy-waves," which are contained within a single wind-gust. t Upon his computation, and as a result of innumerable tests, their flow is at the rate of as many as 900 a minute. And here comes the kernel of the whole' research.
Herr Rumpler is convinced that these minute wind-waves, forming the internal structure of bigger trends of air, cause certain feathers of a bird's outstretched wings to vibrate in such a fashion that the bird extracts from them not only support, but also a definitely propulsive foree—and this without any need to flap its wings.
This leads to the second and critical stage of the Rumpler' search. Can man, with a flexible, scientifically-constructed wing, imitate nature to the extent of profiting, as does the bird, by the inmate power contained within! every gust of wind?
"The evolution of such a wing would eliminate the present system of driving a flying machine through the air, like a ship across the water, by means of revolving screws. I might also, it is calculated—save for the provision of a lowpowered motor for purposes of ascent into a suitable wind-stream—inaugurate an era of an
Text read from the printed page and cleaned; old type leaves the occasional error.