第2章 CHAPTER I. THE DAWN OF AERONAUTICS.(2)

Roger Bacon, Melchisedeck-fashion, came into existence at Ilchester in 1214 of parentage that is hard to trace. He was, however, a born philosopher, and possessed of intellect and penetration that placed him incalculably ahead of his generation. A man of marvellous insight and research, he grasped, and as far as possible carried out, ideas which dawned on other men only after centuries. Thus, many of his utterances have been prophetic. It is probable that among his chemical discoveries he re-invented gunpowder. It is certain that he divined the properties of a lens, and diving deep into experimental and mechanical sciences, actually foresaw the time when, in his own words, "men would construct engines to traverse land and water with great speed and carry with them persons and merchandise." Clearly in his dreams Bacon saw the Atlantic not merely explored, but on its bosom the White Star liners breaking records, contemptuous of its angriest seas. He saw, too, a future Dumont circling in the air, and not only in a dead calm, but holding his own with the feathered race. He tells his dream thus: "There may be made some flying instrument so that a man sitting in the middle of the instrument and turning some mechanism may put in motion some artificial wings which may beat the air like a bird flying."

But he lived too long before his time. His ruin lay not only in his superior genius, but also in his fearless outspokenness.

He presently fell under the ban of the Church, through which he lost alike his liberty and the means of pursuing investigation.

Had it been otherwise we may fairly believe that the "admirable Doctor," as he was called, would have been the first to show mankind how to navigate the air. His ideas are perfectly easy to grasp. He conceived that the air was a true fluid, and as such must have an upper limit, and it would be on this upper surface, he supposed, as on the bosom of the ocean, that man would sail his air-ship. A fine, bold guess truly. He would watch the cirrus clouds sailing grandly ten miles above him on some stream that never approached nearer. Up there, in his imagination, would be tossing the waves of our ocean of air.

Wait for some little better cylinders of oxygen and an improved foot-warmer, and a future Coxwell will go aloft and see; but as to an upper sea, it is truly there, and we may visit and view its sun-lit tossing billows stretching out to a limitless horizon at such times as the nether world is shrouded in densest gloom. Bacon's method of reaching such an upper sea as he postulated was, as we have said, by a hollow globe.

"The machine must be a large hollow globe, of copper or other suitable metal, wrought extremely thin so as to have it as light as possible," and "it must be filled with ethereal air or liquid fire." This was written in the thirteenth century, and it is scarcely edifying to find four hundred years after this the Jesuit Father Lana, who contrived to make his name live in history as a theoriser in aeronautics, arrogating to himself the bold conception of the English Friar, with certain unfortunate differences, however, which in fairness we must here clearly point out. Lana proclaimed his speculations standing on a giant's shoulders. Torricelli, with his closed bent tube, had just shown the world how heavily the air lies above us. It then required little mathematical skill to calculate what would be the lifting power of any vessel void of air on the earth's surface. Thus Lana proposed the construction of an air ship which possibly because of its picturesquesness has won him notoriety. But it was a fraud. We have but to conceive a dainty boat in which the aeronaut would sit at ease handling a little rudder and a simple sail. These, though a schoolboy would have known better, he thought would guide his vessel when in the air.

So much has been claimed for Father Lana and his mathematical and other attainments that it seems only right to insist on the weakness of his reasoning. An air ship simply drifting with the wind is incapable of altering its course in the slightest degree by either sail or rudder. It is simply like a log borne along in a torrent; but to compare such a log properly with the air ship we must conceive it WHOLLY submerged in the water and having no sail or other appendage projecting into the air, which would, of course, introduce other conditions. If, however, a man were to sit astride of the log and begin to propel it so that it travels either faster or slower than the stream, then in that case, either by paddle or rudder, the log could be guided, and the same might be said of Lana's air boat if only he had thought of some adequate paddle, fan, or other propeller. But he did not. One further explanatory sentence may here be needed; for we hear of balloons which are capable of being guided to a small extent by sail and rudder. In these cases, however, the rudder is a guide rope trailing on earth or sea, so introducing a fresh element and fresh conditions which are easy to explain.

Suppose a free balloon drifting down the wind to have a sail suddenly hoisted on one side, what happens? The balloon will simply swing till this sail is in front, and thus continue its straightforward course. Suppose, however, that as soon as the side sail is hoisted a trail rope is also dropped aft from a spar in the rigging. The tendency of the sail to fly round in front is now checked by the dragging rope, and it is constrained to remain slanting at an angle on one side; at the same time the rate of the balloon is reduced by the dragging rope, so that it travels slower than the wind, which, now acting on its slant sail, imparts a certain sidelong motion much as it does in the case of a sailing boat.