‘Theaetetus is flying’: Plato presented the sentence as a paradigm falsehood; good Aristotelians later argued that its falsity was apodictically certain. For the impossibility of human flight seemed to follow ineluctably from two seemingly irrefragable truths. First, there’s no flying without wings. ‘Flight,’ according to Aristotle, ‘is the form of locomotion peculiarly appropriate to birds,’ and it is properly accomplished by means of wings. (A stock example in the ancient logic books ran: ‘If the earth flies, it has wings.’) Secondly, men have no wings. According to Aristotle again, ‘birds cannot have an upright posture like men. For the nature of their wings is useful to them given the way in which their bodies are in fact constituted, but if they were upright the wings would be useless – as they are on the Cupids which painters depict. And it is clear that no man – nor anything else of a similar form – could be winged: for the possession of wings would be useless for them in their natural movement, and nature makes nothing contrary to nature.’ Only things with wings can fly; no man can have wings: therefore no man can fly. Flying is strictly for the birds.
The New Science of the 17th century disdained such metaphysical proofs. But in its own way it was little more hospitable to the idea of human flight. Thus Descartes: ‘It is indeed possible – metaphysically speaking – to make a machine which will support itself in the air like a bird; for birds themselves, in my view at least, are just such machines. But it is not possible scientifically or practically speaking; for one would need forces at once so subtle and so powerful that they could not be fashioned by men.’ The Cupids which painters depict are not, perhaps, conceptually repugnant, but they are scientifically absurd.
Physically or metaphysically excluded, human flight was also morally undesirable. Seventeenth-century authors imagined the horror of aerial warfare and the mischief of flying felons. And in the 18th century Samuel Johnson repeated the warning:
What would be the security of the good, if the bad could at pleasure invade them from the sky? Against an army sailing through the clouds neither walls, nor mountains, nor seas, could afford any security. A flight of northern savages might hover in the wind, and light at once with irresistible violence upon the capital of a fruitful region that was rolling under them. Even this valley, the retreat of princes, the abode of happiness, might be violated by the sudden descent of some of the naked nations that swarm on the coast of the southern sea.
Yet if the moral sciences were discouraging, fiction and folklore offered to inspirit the imaginative optimist. Witches rode broomsticks; angels and devils swooped through space; Greek fables spoke of airborne heroes. And in fact Icarus and Phaethon found optimistic emulators in plenty. Most were cranks and many were charlatans. In 1507 Damian, Abbot of Tungland – variously known as ‘the Italian’ or ‘Master John, the French leech’ – undertook to fly from Scotland to France. ‘To that effect he had a pair of wings made from feathers. When they were fastened to him, he flew from the castle walls of Stirling, but at once fell to the ground and broke his thighbone. He attributed the blame for his failure to the fact that there were some hen feathers in the wings, which desired and yearned for the earth and not the sky.’ In October 1751 the Whitehall Evening Post carried a description of Signor Grimale’s flying-machine, with which he had ‘once adventured to cross the seas, which was from Calais to Dover, and the same morning arrived in London’. Signor Grimale proposed to give a demonstration flight in London on the King’s birthday, setting off from the top of the Monument and circling the City; and he offered flying tuition at 50 guineas a time. He prudently left England before the promised demonstration. It is not recorded how many guineas he pocketed. In 1770 the Abbé Desforges of Etamples advertised a new flying machine: a bargain at 100,000 livres, it had a top speed of some 70 mph and could cover anything up to eight hundred miles a day. Finding no customers, Desforges himself took a machine to the top of the Tour Guinette and was launched by four tough peasants. He plummeted directly to the ground.
And so it was with all the early birdmen. Cautious spirits, like Leonardo da Vinci, were content to scribble down designs whose grotesque impracticality they did not submit to empirical proof. The temerarious, who trusted themselves to the air, were lucky to escape with a few broken bones – and never travelled more than a yard or so in the horizontal plane.
Clive Hart’s Prehistory of Flight lists in an appendix some fifty attempts at heavier-than-air flight undertaken – or allegedly undertaken – before 1783. The second and more lively half of his book, on ‘Practice’, recounts the histories of some of these engaging lunatics. The first half concerns ‘Theory’: there is a chapter on the general problems thought to confront human flight, and a chapter on the special contribution of Leonardo to the history of aeronautics.
Since flight is the locomotion of birds, and birds are model aeroplanes, the science of ornithology provided an important part of the theoretical background against which the comedy of flight was played. The question of exactly how birds fly was much debated. Some theorists thought in biological terms, some invoked the latest theorems of mechanics, some even observed birds in flight. The theories often reached a considerable degree of complexity, and Hart’s narrative chronicles a number of novel insights and ingenious speculations. But for the most part the story is repetitive and somewhat depressing: for centuries little advance was made over Aristotle, whose brief remarks about bird-flight in his essay on the ‘Progression of Animals’ remained the basis for most subsequent thought. Reflection on the locomotion of birds presupposes some notions about the medium through which they travel – about the air. And early thought about the nature of the air is the subject of Hart’s opening chapter. Here, too, the tale desponds. Aristotle’s views about air, one of his four ‘elements’, were unavoidably infantile: for two thousand years his successors made little progress, and the sciences of physics and chemistry were slow to leave the nursery.
Hart’s book contains a mass of recondite information on all these things. The birdmen parroted one another’s theories. They gulled the public – and as often as not rooked them when they hawked their discoveries. Hart does not swallow their extravagant claims, nor does he duck the difficulties of their tortuous theorisings. He does not crow over their crudities, snipe at their stupidities, rail at their rawness, or grouse at their green gaucherie. His clients are cuckoo, and his book is sometimes something of a lark. It is, moreover, less a bird’s-eye view of its subject than a jackdaw’s nest. But it is also a serious and scholarly study, and I have not noticed a single bad pun.
Yet it is in some ways a strange volume. Shape, size and style suggest the coffee table. The margins are wide, the paper is heavy, the dust-jacket is royal blue. There are excellent illustrations, clearly and generously reproduced (and the best of them having no evident connection with the text). On the other hand, the print is small, technicality is not avoided, and some sixty pages of the book are occupied by learned footnotes and a vast bibliography (which begins by describing a selection of 28 manuscripts ‘relevant to the creation of the birds’). It is a book which seems to aim at two readerships and to risk missing both. Historians of science, who will be impressed by the annotation, may wonder why the text presents only a partial history of the subject. Other readers, welcoming the text as an entertaining and erudite essay on a topic of mesmeric appeal, may wonder why they are obliged to purchase a pound or so of annotation as a make-weight. However that may be, I suspect that any reader with a taste for the ludicrous and the laudable in human aspiration will enjoy Hart’s spins and rolls in the thin air of early aviation.
One question which every reader will ask is this: why did it take so long for men to fly? Man’s natural element is no doubt earth: yet the water was quickly conquered – why should the resistance of the air have been so much stronger? The same question presented itself to the early airmen themselves, for whose efforts the apparent parallel between air-travel and water-travel was a persistent encouragement. Hart hints at an answer of a moral or spiritual sort: flying is contrary to human nature; the air is an alien medium – dangerous, uncertain, a region of fear and darkness. Men ought not to reach for the sky. But while it would be as foolish to ignore as it is hard to understand such moral qualms, we may perhaps reasonably guess that it was not primarily spiritual doubt which kept men from the heavens.
A more appealing answer blames ignorance, technical and theoretical. Technological difficulties indeed existed, as Descartes indicated: for a flying-machine must be both light enough to get lift and powerful enough to achieve thrust, and these two desiderata are hard to combine. Again, early theories of bird-flight were certainly false; and, more generally, the crude physics and the cruder chemistry of past centuries could not sustain a theory sophisticated enough to account for the paradoxical flight of things which are heavier than air. Yet it is not clear that such deficiencies are in themselves adequate to explain the long failure of early attempts at flight. The first successful aviators did not use new-found materials, new-made machinery or newfangled technological devices. And although practice may often and in subtle ways depend on theory, it is hardly to be believed that without a science of aeronautics no pilot would have flown. Did the first ship-builders need a theory of hydrodynamics? When the Argo was launched, was the water any better understood than the air, or the movement of fish than the movement of birds?
Hart’s history implicitly suggests an answer of a different kind. It is as though the early fliers suffered from a blinkered imagination. They concentrated their forces, in effect, on the second of the two premises in the ‘Aristotelian’ argument against flight; and they were determined to refute the Aristotelian contention that men cannot possess wings.
Legend suggested two possible modes of refutation: men might become aviators or men might become aeronauts. Whereas the aeronauts sought to construct airships in which they might sail the skies, the aviators hoped to turn themselves into artificial birds by acquiring wings of their own. As an emblem of hope the aviators might have adopted Menippus, who – in Lucian’s satirical Icaro-menippus – flew to Olympus by equipping himself with the wings he had torn from an eagle and a vulture. As a perilous warning they had Icarus, whose fate they normally shared. The aeronauts might have been animated by a different romance of Lucian: in his True History he describes another aerial journey in which the travellers, themselves wingless, voyage in a flying-machine. Their mythical warning was given by Phaethon, whose fate they normally shared.
The project of the aeronauts was, for purely technical reasons, more likely to succeed than that of the aviators. Yet both aeronauts and aviators had the same blind spot: they thought that flying was done by birds, and they strove to manufacture bird-like artefacts which would imitate the birds of nature. For although ships are not in the least like fish, the earliest airships were all designed to look and to behave like birds. In particular, they were designed to flap their wings. It is and was a familiar fact that birds glide and soar with wings outstretched and immobile, but it was the powerful beating of wings which engrossed the airmen’s imaginations. And so they either fluttered their own feather-clad arms or else invented ever more ponderous ornithopters. But the flappers never took off.
Determined to refute the second premise of the ‘Aristotelian’ argument, they did not think to question the first: why suppose that wings, and in particular flapping wings, are a sina qua non for flight? Fiction had long managed to reject the supposition: the travellers in Lucian’s True History are in a flying boat – their ship was sucked from the sea by a whirlwind and then sailed before the winds on the upper surface of the air. Flying boats retained a place in popular folklore. In 1670 Francesco de Lana actually designed a flying-machine in the form of a boat supported by four vacant copper spheres. Yet it was not until 1783 that wings were fruitfully forgotten and the problems of flight were simplified and solved.
The Montgolfier balloon was not in the least bird-like. It had no beak and no feathers. Nothing flapped. The startling machine made no great demands on technology, and the ‘theory’ explaining its behaviour was well within the competence of any Aristotelian scientist. The stunning novelty was conceptual, a product of the human fantasy, of reason in her most exalted mood. A dull imagination had kept men grounded. Once imagination soared, the rest followed easily enough.