Few, if any, problems have so strongly influenced the imagination and exercised the ingenuity of mankind as that of aërial navigation. There is something in our nature that rebels against being condemned to the condition of “featherless bipeds” when birds, bats, and even minute insects have the whole realm of air and the wide heavens open to them. Who has not, like Solomon, pondered upon “the way of a bird in the air” with feelings of envy and regret that he is chained to earth by his gross body; contrasting our laboured movements from point to point of the earth’s surface with the easy gliding of the feathered traveller? The unrealised wish has found expression in legends of Dædalus, Pegasus, in the “flying carpet” of the fairy tale, and in the pages of Jules Verne, in which last the adventurous Robur on his “Clipper of the Clouds” anticipates the future in a most startling fashion. Aeromobilism--to use its most modern title--is regarded by the crowd as the mechanical counterpart of the Philosopher’s Stone or the Elixir of Life; a highly desirable but unattainable thing. At times this incredulity is transformed by highly-coloured press reports into an equally unreasonable readiness to believe that the conquest of the air is completed, followed by a feeling of irritation that facts are not as they were represented in print. The proper attitude is of course half-way between these extremes. Reflection will show us that money, time, and life itself would not have been freely and ungrudgingly given or risked by many men--hard-headed, practical men among them--in pursuit of a Will-o’-the-Wisp, especially in a century when scientific calculation tends always to calm down any too imaginative scheme. The existing state of the aërial problem may be compared to that of a railway truck which an insufficient number of men are trying to move. Ten men may make no impression on it, though they are putting out all their strength. Yet the arrival of an eleventh may enable them to overcome the truck’s inertia and move it at an increasing pace. Every new discovery of the scientific application of power brings us nearer to the day when the truck will move. We have metals of wonderful strength in proportion to their weight; pigmy motors containing the force of giants; a huge fund of mechanical experience to draw upon; in fact, to paraphrase the Jingo song, “We’ve got the things, we’ve got the men, we’ve got the money too”--but we haven’t as yet got the machine that can mock the bird like the flying express mocks the strength and speed of horses. The reason of this is not far to seek. The difficulties attending the creation of a successful flying-machine are immense, some unique, not being found in aquatic and terrestrial locomotion.