Chapter THE SECOND: Man as the MIMIC of Nature (1)
I
PRELIMINARY CONSIDERATIONS
We have taken a glance at the bridges made by Nature (pp. 3-4), and now we have to consider their influence on the genesis and development of handicraft. This difficult study has been neglected by men of science; not even Darwin said a word about natural bridges, though they were models to be copied by the sedulous ape in primitive men; and so we must try to be as thorough as possible, within the limits set by a brief chapter.
Where and how is a beginning to be made? The useful and necessary thing is to visualise the fact that varied hints on bridge-building accompanied the descent of man, so the influence of their utility was active through all the linked growth in that organic chain by which the earliest men and their nearest allies were united. Sooner or later the mere use of natural bridges would generate in some minds a desire to copy them; and although we are quite ignorant as to when this desire came for the first time out of the darkness, yet we may suppose, without any great extravagance, that it belonged to the same period of handicraft as the earliest manufactured tools and weapons, which were a development from stone clubs and spears fashioned into shape by earthquakes and volcanoes, the first armourers of the Stone Age. As soon as a tribe, guided by a savage of genius, began to copy three or four object-lessons in Nature’s perennial school for mimics, the imitation of several others would be suggested by the same trend of thought, sooner or later. It is reasonable to believe that hand-made weapons preceded hand-made bridges, as hunting and fighting were the strongest motive-powers behind human needs and actions. To slay was the herald of to build, so the first bridges of handicraft ought to be placed in a likely inference among the later doings of Palæolithic hunters and warriors.
A horrible slowness marked each advance from a bad copy of a natural bridge to a slightly better one. In fact, only a few brilliant creative minds--not more than two or three thousand--separate our own social order from the strife of Palæolithic savages. Into the coarse dough of humanity an infrequent genius has put some enchanted yeast. And we must needs believe that the dead routine of imitation, to which human nature has ever been enslaved, held primeval man even more relentlessly than it holds ourselves. One misfortune more than any other delayed a creeping progress: it was the fact that mankind had no cause to fear the most intelligent creatures among the lesser organisms. If snakes and beasts of prey had been as clever as were bees and ants and beavers, men could have saved themselves from extermination by one means only--by a rapid advance from frequent good ideas into great achievements. Day after day the large human brain would have been called upon to produce large protective thoughts, and, had it failed to produce them day after day, the human race would have been food for enterprising rivals. We have no guess why Providence withheld from mankind this high discipline, this fateful choice between death and a swift intelligence; but we do know that the most dangerous of the lesser organisms have been the least quick-witted, and that men in their intercourse with natural things have shown a lethargic mimicry. Their cave-dwellings were stolen from cave-lions and cave-bears; their pit-dwellings were copied from the holes and tunnels burrowed by many animals; and in their lake-dwellings they collected hints from five sources: natural bridges, the platforms built by anthropomorphous apes,[34] the habits of waterfowl, the beavers dam and “lodge,” and the nests of birds. In the round hut, which was made with branches and wattle-and-daub, stick nests were united to the plasterwork of rock-martins. Yes, a good workman in the construction of mud walls does no more than rock-martins have done in all the ages of their nest-building. When these birds make their nests they use wet loam stiffened with bits of straw, and each layer is allowed to harden before another is put on in a thickness of about half an inch for a day’s work.[35]
Even more remarkable is the fact that men may have borrowed from several birds the idea which enabled them to pass from round huts into oblong cabins. In Australia, for instance, there are three birds--genera of the same family--that build arched bowers with long sides; and Darwin tells us to regard them as “co-descendants of some ancient species which first acquired the strange instinct of constructing bowers for performing their love-antics.” One species of Australian bower-birds, the fawn-breasted variety, erects a platform of sticks as a foundation for its gabled hall of courtship, that measures nearly four feet in length and eighteen inches in height. This structure is charmingly decorated, and if we could magnify it to the size of Westminster Hall we should be amazed by its beautiful architecture. Unmagnified, it is a model to all primitive men, for it shows far more invention than a wigwam or than a charcoal-burner’s hut.
As soon as a student begins to understand what mankind has copied in Nature’s wonderful school for mimics, he cannot fail to take delight in natural bridges and their influence on handicraft. At first he is humbled painfully by the small amount of creative wit that a million years or so have gleaned from the big human brain; but soon the novelty of feeling humble is more attractive to him than the vile habit of flattering human nature.[36]
II
AMONG THE HERALDS OF MAN
It was during the Upper Miocene age that two or three big apes migrated into Europe, probably from Africa, and passed from explorers into colonists. One of them was the Dryopithecus, a creature almost as tall as a man, and closely allied to Hylobates. He illustrated that organic art of caricature in which young Dame Nature excelled, many of her experimental efforts having Gargantuan humour in their shapes and proportions.
When food was scarce the Dryopithecus became a nomad, a sort of four-handed Odysseus who was very well able to fight his own battles, whether he wielded a heavy stick, or hugged his foe, or from the shelter of a tree dropped missiles that cracked heads and made backbones exceedingly painful. Hugging seems to have been his _forte_, after clawing and fierce blows had prepared the way for a close embrace; and by his expert ferocity in defence and in attack he earned for himself the right to be a forerunner of several entertaining creatures, notably the gorilla and the chimpanzee and primitive man. He was inquisitive enough to use every natural bridge put in his path by good fortune.
At first I see him on four sorts of natural bridge, and no fault can be found with his activity. He crawls along fallen trees over some torrents and chasms; across a flooded river here and there he leaps in a shambling, lopsided fashion, when stepping-stones and boulders rise above water-level; he roams into hilly districts where many a ledge of rock spans a dangerous gap; but he enjoys himself most of all when a suspension bridge of branches enables him to amble from tree to tree across a deep-lying river pent up between high cliffs.
In these four bridges, each of them generic, Nature has arrived at utility in her usual manner, by alternating growth and violence. The fallen tree, for instance, from which all timber bridges have been evolved by handicraft in a sequence of gradual improvements, belongs to the utility of Nature’s violent moods; and this applies also to the bridge of stepping-stones. Earthquakes and floods distributed boulders over the beds of rivers, and from these boulders handicraft has developed piers and abutments. On the other hand, a bridge of long boughs--and I have used many a one myself--is a symbol not merely of growth but of abundance, and also of endurance. But it is not to be looked upon as the only suspension bridge along which our arboreal ancestry capered, and from which primitive mankind took, and take, hints in bridge-building. Let us remember also the pendent bridge of lianes, and of other tough creeping plants, which in many warm countries grew, and grow, from tree to tree, forming strong cables. On such a high-swung bridge I can see the Dryopithecus, suspended by his hands, and learning tricks as a gymnast, while his mate squats between the fork of a branch and collects fleas from her baby.
When photographs of natural bridges lie around me on a table, there is another vision that comes before my mind in a succession of vivid pictures. I behold a shaggy little animal, partly an ape, partly a man, who stands upright on a fallen tree; below his feet a river in flood foams among rocks; and over there, beyond the peaked hills, a blood-red sunset makes a wondrous tragedy of colour. Somehow the little animal is awed by the flaming sky, and stares at it fascinated, his protruded mouth wide open, and his teeth gleaming. His arms are thin, sinewy, capable, hairy, and very long; they hang at full length, and their prehensile fingers grasp two sticks, one long and pointed, another short and knobbed. His breastbone looks weak as his shoulders droop forward, and horizontal lines of wrinkled skin run from each armpit across the narrow chest. His legs are short and somewhat arched; and their feet grip wood as a habit. The eyes, overhung by a ledge of bone, shimmer with a peculiar suspicion, an instinctive cunning, very vigilant and fierce, that protects even tired sleep with the alertness of a sentinel. The body is daubed with yellow ochre and iron ore, as if to rival the coloured life seen everywhere in Nature; but through this decoration much uneven hair is noticeable, and a coarse beard surrounds the face with a ruff rather similar to that which now gives pride to the _Cebus capucinus_. The head is becoming human, a real Pandora box, whence many banes and a few blessings will escape continually, and spread far and wide over the earth. At present this creature is a wild beast in the terrible nursery stage between apehood and savage manhood. Already he has lost the athletic ease and grace of his tree-top cousins. Not only is he out of joint with them, but his own lot is very perilous, a never-ending war against hardships and dangers. Beasts of prey know how weak he is; most animals outrun him; birds in their swift flight escape from his weapons, and he feels rage and jealousy when monkeys at play leap long distances from bough to bough. Out of his nature comes a pitiless hatred for all living creatures. Do you not see this earthling, this Adam of Evolution, part ape and part man, standing alone on a windfall bridge, with a river in flood below his feet, and the sun a radiant crescent, blood-red, dipping below that far horizon of peaked hills?
And yet this biped has been moved by the sunset, and also by an idea of his own, whose history can be read in deep lines of ploughed earth that run from the bridge to a wood over there, a hundred yards away. At this distance from the river a tall tree was blown down, and a tribe of ape-like men, guided by their leader, dragged it to the bank-side and put it across the waterway, taking long days over the wonderful task. Nature at last has discovered a mind that can think in imitation. Her tree-bridge has a rival.
At this moment the picture changes. A female creature appears, accompanied by several children. She is uglier than the male, because she suffers much more; her family grows too fast, and for a long time its members are unfit to defend themselves. Never for an hour can she put aside her motherhood. Other animals are occasional parents, because their young are soon able to do their own business; while she, our Eve of Evolution, for ever anxious about her helpless little ones, is an incessant mother through the few brief years of her fertility. Perils encompass her and them, and in a short time she is worn into old age. But she loses her youth creatively; there is not a privation nor a pain that her constant motherhood fails to make into a spiritualising of the heart, into a _Vita Nuova_, into the starting-point for a fresh development. So she is humanised by suffering and love-humanised in spirit, that is to say--long ages before her body has matured into womanhood. It is she who endows children with quickened minds and with social inclinations; and it is she who encounters with a yielding but tenacious courage the wild beast that male passions breed and perpetuate. Also--and this is very important--she is by temperament a practical worker, whereas the male is not; he thinks all the time of adventure, and his moods are incalculable. Even his paternity is coarse-handed, and subject to furious greeds and lusts. His brain is active enough to be awed by the strife of Nature and weak enough to be crippled by a little reason. His character threatens to check his evolution. Where the climate is hot, and food grows abundantly, he makes no progress; bad times alone compel him to work, and to pass very slowly, with a dogged reluctance, from handicraft to handicraft. His higher education begins when he chips a stone into a pointed weapon and feels the rhythmical enjoyment that accompanies invention and manipulation. In fact, handicraft is the earliest public school, the first university; it helps motherhood to transform the brute male into a being somewhat better,[37] a primeval savage. Yet naturalists have confirmed themselves in three bad habits: they say too little about handicraft, they admire man far too much, and they patronise woman. When they do not bury Woman in the term Man, they glance at her with a condescending half-pity, as bibliophiles glance at second or third editions; and so it is worth while to do some justice to our primitive foremother, the Eve of Evolution.
With her incalculable partner, the irrational male, she and her family wander from district to district. At times they settle under a rock-shelter or in a cave, and make footpaths from it to watering-places and hunting-grounds. Here and there a river is crossed by stepping-stones, and more than one ravine is spanned by branches and by a fallen tree. What is their attitude to these things? The windfall tree-bridge, like every other gift from Nature, is a bane to them as well as a boon, for it is a road open to dangerous animals; as such it is a thing to be guarded, and many a fight in its defence occurs, creating traditions of bravery which are long remembered.
Further, as time goes on, and the progenitors of man become more human, the pressure of competitive life draws ever more and more attention to the incompleteness of natural bridges. For example, stepping-stones may be useless when they are needed most of all, in wet seasons and after storms; and the tree-bridge is so narrow that warriors cross it only one by one, so their slow attack gives a terrible advantage to a brave defence. These hindrances, so obvious and so unpleasant, make appeal to the inventive faculty that a few men possess. Not much is required. From four or five seedling ideas a great many improvements will grow; and now is the moment for us to choose a vague tentative date for the beginning of this gradual development.
Most people are bored by prehistoric archæology, because its earlier periods are as undated as is the oblivion of coma. So a date in obscure history, however tentative it may be, is very helpful; the mind rests on it, somehow, anyhow, and feels that the lost legions of the dead years left some oases in the Saharas of ancient time. And this point is not the only one that concerns the general reader who _does_ generally read. In recent years the antiquity of handicraft has been extended very much by a “find” of eagle-beaked flint implements, with other tools, below the Pliocene deposits on the East Anglian Coast. The eagle-beaked flints are undoubtedly of human manufacture, and they carry back the ancient stone period of man to the Tertiary times. Sir Ray Lankester writes on this important subject, and his knowledge helps us a great deal, though we have to recover it from entangled sentences. For example[38]:--
“Evidence has been for twenty years or more in our
possession (in the form of stone implements) of the
existence of man in Europe in the warm period which preceded
the Pleistocene, with its glacial clays and drifts and its
gravels deposited on the sides of existing river valleys,
sometimes 800 feet above the level of the bed to which the
stream has now worn down its excavation, many miles wide.
The discovery within the last four years of beautifully
worked flint implements of the shape of an eagle’s beak
(called ‘rostro-carinate’) and of other serviceable forms
below the marine Pliocene shelly sands--known as the ‘Red
Crag’ in Suffolk--separates the migrations and mixtures of
human tribes and groups, of which we have any knowledge, by
a huge chasm of geologic time from the date of the earliest
European population. The best geologists have come to the
conclusion that half a million years (and it may well be
twice as many) separate us from the days before the Crag Sea
laid down its shelly deposits on the East Anglian Coast. Yet
there were skilful men--not mere ape-like creatures using
sticks and roughly-broken stones, but men capable of making
and admiring symmetrical, well-finished flint tools, and of
using them to clean skins and to plane wood--living a human,
creative, dominating life here in Western Europe in those
immensely remote days. Probably enough, as great a period as
separates those skilful men from us separated them from the
earliest unskilful ‘commencing’ men of the tropical zone.”
Yes, probably enough, but yet we must not suppose that handicraft in Western Europe has ever had a standard of uniform merit. As our own work is very often inferior both to that of the Romans and to that of the Middle Ages, so the eagle-beaked tools may denote nothing more than a local industry which a man of genius had originated. No other implements have been dug up from Pliocene deposits in other European localities, hence students of art and architecture cannot accept the generalisation advocated by Sir Ray Lankester. As well suppose that the whole of Western Europe produced in the same age many painters equal to the Van Eycks, or many bridge-builders of a piece with Caius Julius Lacer, or the good Saint Bénézet. It is enough to believe that at a date to be known vaguely as 500,000 B.C., a craftsman of genius lived and laboured in a district of Western Europe, now called the East Anglian Coast. How far his influence extended, or how long it lasted, we have no inkling yet; but it may have been the influence, not of a rare genius, but of a school tradition which migrating tribes had spread through many parts of Europe. Anyhow, the eagle-beaks are historic facts and their manipulative skill gives us the right to make reasonable inferences.
For example, we may infer that if the craftsman who made an eagle-beaked tool showed intelligence in some other useful ways, he did no more than common justice to his humanity. Suppose he cut down a tree with his flint axe, choosing one that grew aslant over a chasm or across a river; or suppose he piled stepping-stones together in the middle of a waterway, and then used this pier as a support for two tree-trunks whose far ends rested on the banksides. Neither of these ideas has more mother-wit than that which has enabled ants to bore tunnels under running water, and to make active bridges by clinging to each other in a suspension chain of their wee brave bodies. Not many human minds in any period of history have been as diligently rational as ants; but let us risk the conjecture that the first advance in bridge-making began among the rostro-carinate workmen probably more than half a million years ago.
To cut down a tree, in order to get a bridge at a chosen place, was a good idea in primitive enterprise, but it was not enough; it gave but little additional help in tribal wars, since it repeated the narrow footway, the main drawback of windfall tree-bridges. Two or three trees laid side by side were necessary, and at least two piles of stepping-stones to carry enough trees over a fairly wide river. Such were the first improvements that war and social life demanded from the wit of primitive mankind, and often they were demanded in vain for many long ages. Even at the present time there are tribesmen who feel well pleased with themselves when they make single and double tree-bridges. I am told, for instance, by Mr. T. Beddoes, a traveller and trader in Equatorial Africa, that often in his wanderings he has made and used a tree-bridge to cross a narrow creek, following a native method for the sake of its ready convenience. “The natives,” he writes, “cut down the tallest trees on a bank of the waterway that they intend to bridge, then they make a handrail with bush-rope fastened to short upright sticks which are placed about three feet apart. Bush-rope is made from creepers or from long cane vines. Sometimes an attempt is made to flatten the upper surface of the tree; but this work is uncommon, as African natives are lazy; they detest manual labour. There are trees that grow to an enormous height; one of them measured a hundred feet odd, so fairly wide creeks and streams can be bridged. But canoes are the favourite means of crossing rivers; they carry light loads well enough, and they need less labour than bridge-building.”
This peep into the aboriginal mind reveals a dire stagnation. But although no other thing in Nature is less uncommon than human initiative, yet the men of the eagle-beaked tools may have made tree-bridges, and also such stone bridges as the lintel-slabs at Wycollar (p. 60). For this work required nothing more than imitation, while the eagle-beaks added some invention to a deft handicraft. Many an earthquake had made a slab-bridge, and other models were formed by the lava from volcanoes which hardened into a thick crust over many gaps in the land.
From these bridges--a tree cut down with a flint axe, and a single boulder or slab laid from bank to bank of a stream--came three lines of descent in very slow, yet fertile handicraft; and to the history of each a long book could be given. Let me name them one by one:--
1. The Slab-bridge with stone piers.
2. The Tree-bridge with stone piers.
3. The Tree-bridge with timber piles.
III
THE SLAB-BRIDGE WITH STONE PIERS
In this we follow an evolution from unhewn fragments of rock upheld by stepping-stones to Cyclopean slabs of hewn granite and marble supported by well-made stone piers. The halting development of this bold stonecraft was loved and fostered by that original people which for convenience we call Iberian, and which at some unknown period migrated from Asia, “and swept round Europe, whilst a second branch colonised the Nile basin and Northern Africa, and a third streamed east and occupied China and Japan. The master idea in the religion of this people was the cult of ancestors, and the rude stone monuments, menhirs, cromlechs, and kistvaens they have left everywhere, where they have been, all refer to commemoration of the sacred dead. The obelisk in Egypt is the highly refined menhir, and the elaborate, ornamented tombs of the Nile valley are an expression of the same veneration for the dead, and belief in the after life connected with the tomb, that are revealed in the construction of the dolmen and kistvaen.”[39]
What could have been simpler than the building methods of the Iberians? We see them at Stonehenge, which dates from about the year 1680 B.C., according to the astronomical calculations of Sir Norman Lockyer and the late Mr. F. C. Penrose.[40] Here we have the primitive circle of large stones, and the rugged trilithon (two rude uprights, or menhirs, connected by a long table slab or lintel). There is a feeling for massive construction, but it is barbaric. The clapper bridges over Dartmoor rivers belong to this elementary craftsmanship. Each is a cromlech repeated in several spans over water, no matter when it was built (p. 100). Among the ancient Egyptians there were kindred bridges; and the Chinese have managed to preserve in a formidable handicraft an Iberian fondness for the trilithon. Mr. O. M. Jackson tells me that many slab-bridges in Sichuan have lintels about twenty feet in length; they are decorated by sculptors with a dragon’s head and tail at the junction of two lintels and a stone pier. Every dragon’s head looks upstream, and the tail curls out on the downstream side; so the slabs appear to rest for security on the back of a guardian dragon.
There is a Chinese bridge of lintel-slabs, concerning which very different descriptions have been written, but even the most moderate account makes it more than four and a half times longer than the Pont Saint-Esprit (p. 293). Gauthey writes about it as follows:--
“At Loyang, in the Province of Fo-Kien, on an arm of the
sea, there is a bridge with three hundred spans; its
construction went on for eighteen years and employed
twenty-five thousand workmen. Technically it belongs to the
same class as the bridges of ancient Babylon, which are said
to have been made with long and flat stones laid from pier
to pier. If Loyang Bridge be 8800 metres in length, as some
writers affirm, then its piers will be 4 metres 87 in
thickness, and its spans in width will measure 24.36 metres.
The footway is 22.74 metres. The long slabs are 5 metres
thick and 3 metres wide. As for the piers, they are 23
metres in height, and bear marble lions carved from blocks 7
metres long.”
Gauthey gives a drawing of this bridge, and his measurements are taken from the Atlas of Martimmart. They have an air of great exaggeration. As Gauthey remarks, “It is difficult to believe that the tabular stones are as large as they are presumed to be: their bulk is more than threefold greater than that of the obelisk at Rome in the Place de Saint-Pierre. Besides, M. Pingeron speaks of them as being fourteen metres long by a metre and a half in thickness and in width, so he diminishes by a full half the length of Loyang Bridge. Even with this reduction it is a wonderful achievement, more than four and a half times longer than the Pont du Saint-Esprit.”[41]
The dimensions given by M. Pingeron may be accurate; they represent a hugely magnified clapper bridge decorated with sculpture and carried on tall piers for a distance of 4400 metres, in a series of three hundred spans. The marble lions, I suppose, ornament the parapets above the piers, like those on the bridge of Pulisangan (p. 310). Marco Polo visited the province of Fo-Kien, where Loyang Bridge is said to be, and stayed at the city of Kue-lin-fu, known to-day as Kien-ning-fu. Here he was greatly struck by “three very handsome bridges, upwards of a hundred paces in length, and eight paces in width.”[42] Not a vivid description, yet enough to prove that notable bridges in Fo-Kien have had a long history.
IV
TREE-BRIDGES WITH STONE PIERS
The most famous bridge in this kind is the one built by Trajan over the Danube, just below the rapids of the Iron Gate. Trajan required it for his wars against Dacia, which in A.D. 106 he brought to a successful end, the Dacian leader Decebalus being slain and his people subdued. The bridge had played its part, yet Hadrian, the next Emperor, who began his reign ten years afterwards, looked upon it as a dangerous highway, open to incursions from Dacian revolts, and for this reason he destroyed some piers and the footway. Perhaps Hadrian was jealous of Trajan’s work, for two fortified gates and a handful of Roman troops could have defended the bridge against barbarians.
There has been much controversy over this great structure. Its architect was Apollodorus of Damascus, who designed also the Trajan column placed in the centre of the Forum Trajanum. A bas-relief on this column represents the bridge, but in a manner at odds with the written description given by Dion Cassius, who held important offices under Commodus, Caracalla, and Alexander Severus, A.D. 180-229. Dion Cassius wrote a history of Rome, in eighty books, and a small portion of this work has come down to us entire. His evidence then is worth having, and it states that the bridge had twenty piers of hewn stone, 150 feet high and 60 feet wide, with openings between them of 170 feet, spanned by arches. Doubt has been thrown on the accuracy of this description, because the bridge on the Trajan column is unsuited to a span of 170 feet; “nevertheless thirteen piers are still visible out of the twenty, according to Murray’s ‘Handbook.’ The writer has not been able to find any accurate measurement of the width between these piers, but as the ‘Handbook’ speaks of the length of the bridge as perhaps 3900 feet, and as the Conte Marsigli, writing from personal observation, in a letter to Montfaucon, gives the total length as probably 3010 feet, there can be no doubt that the spans were very considerable and that the representation of the design in the bas-belief is almost wholly conventional. The one point as to which it gives clear information, not supplied elsewhere, is that the superstructure was of wood.”[43]
In other words, this colossal work was a descendant of the earliest tree-bridges, in so far as the footway was concerned. Whether arched timbering was carried from pier to pier to uphold the roadway, as in the bas-relief, is a question of no great moment; the horizontal bearing beams would need support, no doubt, since they had to span openings far wider than the longest trees; and it is useless for us to guess in what way this support was carried to them from the lofty piers, which were built with enormous blocks of stone. The main point is that one phase of bridge-building, whose first models were fallen trees lying astride rivers and chasms, seems to have culminated in the masterpiece of Apollodorus of Damascus. Much inferior work of the same kind, very varied and entertaining, has been common everywhere; some of it belongs to Kurdistan, for example (p. 73); and in the Lledr Valley there is a good Welsh specimen called the Pont-y-Pant, whose wooden footway is primitively rustic, and whose piers are fragments of rock gathered from the river-bed and piled together. I have found at Thirlmere a quaint thing which is partly a dam and partly a bridge. The dam, an undulating wall of unmortared stones, has at equal intervals a few angular openings over which wooden hand-bridges are thrown. It would be easy in a shallow river to make a fish-pool by heaping boulders into a dam of this rude sort, and the completed work would rank no higher than the beavers contests against running water. So I tell myself that many a tribe in the great period of prehistoric art, about 50,000 years B.C., ought to have built for itself a bridge as elementary as the Pont-y-Pant and a perforated dam as uncouth as the one at Thirlmere.
From this untutored handicraft we look back again at the great art of Apollodorus, whose vast bridge over the Danube was near the ancient town of Nicopolis. What a long travail in the gestation and birth of infrequent ideas! Even half a million years ago a man of the eagle-beaked tools may have put a boulder under a tree-bridge because the tree was thin and swayed too much on a windy day; half a million years ago, and yet we do not feel ashamed of the Pont-y-Pant!
V
TREE-BRIDGES WITH TIMBER PILES
Let me restate the first periods in their history:--
1. A windfall tree lying astride a gap in the land.
2. A windfall tree dragged from a wood and put astride a gap in the land, perhaps by a tribe of semi-human creatures directed by a superior mind.
3. A savage of genius, perhaps as early as the Tertiary period, cut down a tree in order that it might span a dangerous creek or an abyss in the mountains. Intelligently, with the aid of a flint axe, he copied the work done by many a gale of wind; and in this act of simple mimicry he discovered the first principles of secure bridge-making. The footway was strong, and branches from the tree-trunk gave support to clutching hands. Any bough that blocked up the footway was topped off. Even to-day we find in country woods a good many rustic bridges hewn from tree-trunks, and guarded at the sides by hand rails of dressed branches. Their footways are no wider than the planed surface of a well-grown tree.
4. Another savage of genius, thousands of years later, maybe, took a hint from a troublesome inconvenience which from the first had been present in tree-bridges. The footway being too narrow, he put two or three trees side by side, so that two or three warriors might cross it abreast, instead of weakening their attack by an advance in single file.
But this improvement suggested other changes of much greater value both to war and to social life. However carefully the trees were laid side by side, their rounded surfaces left a valley between them; and gaps were formed by curved trunks and by gnarled excrescences. So the widened footway had drawbacks of its own. Often, on a rainy day, naked feet would slip, for the trees were polished by long use; and many a slip would either break or strain an ankle. Yet the wit of mankind would bear these troubles with a grumbling patience; thousands of years may have passed by unprofitably; but sooner or later a man of genius would perceive that every defect in a bridge suggested an improvement. The valley between the tree-trunks could be filled in with soil and pebbles and turf; a round foothold polished by long use and slippery after rain, could be flattened and roughened; and where the trees diverged from each other, making traps for the unwary, invention could be busy for a long time. Why put the trees close together? If they were separated by half a stride, then covered transversely with brushwood and turf, a much better bridge would be made without much effort. Again, suppose the long beams were thin saplings that shook too much underfoot, particularly when a tribe of shouting warriors ran across them in a hot attack. To steady such a bridge with props would be a great convenience, and timber props would serve as conveniently as boulders and piled stones. A criss-cross of logs made an excellent pier,[44] for example, and forked boughs, which entered into several phases of primitive handicraft, made good piles.[45] We know not when these quite simple improvements gave some dignity to manual work, but their inception needed only a little mother-wit. Some Quarternary men ripened a great deal more in their arts, as painters and sculptors and engravers.
In this monograph several descendants from the aboriginal tree-bridge are studied briefly, and I refer you to the Index. Some varied English specimens are given in Francis Stone’s “Norfolk Bridges”; and from Don Antonio de Ulloa (1716-1795) we can learn how wooden bridges have long been made in the mountainous parts of South America. They “consist of only four long beams laid close together over a precipice,” and they “form a path about a yard and a half in breadth, being just wide enough for a man to pass over on horseback.” Here the beams have a flat surface, and lie together like boards on a floor. It is primitive handicraft of a low sort, for the beams would carry a much wider footway.
VI
SOME TYPICAL TIMBER BRIDGES
As there is no room here for a pedigree of timber bridges, let us choose a few examples which are particularly famous in history. It will be enough if we take three: (1) a prehistoric lake-village, (2) the Pons Sublicius of the Romans, and (3) the wonderful work done in the eighteenth century by two Swiss carpenters, the brothers Grubenmann.
Lake and marsh villages were the highest form of prehistoric bridge-building; their thronged platforms, dotted with round huts, not only put a defence of water between home life and prowling foes, but heralded all the housed bridges that the world has seen during its periods of written history. Whether we study Old London Bridge, or the criss-cross bridges with frail shops in Kashmír (p. 71), or the booth-bridges of China (p. 210 _note_), or the roofed timber bridges of Switzerland (p. 291), we are concerned with a pedigree that starts out from the first Neolithic lake-dwellings. But the later stone period, known as Neolithic, is not very old. Between it and ourselves there is a span of about nine thousand years, or a few thousand years more.[46] But British lake-dwellings are attributed to a time still later, the Bronze Age, whose date in the British Isles may be fixed tentatively at from 1200 to 1400 B.C.[47] Further, as pit-dwellings lasted to the days of Tacitus among some Germanic tribes,[48] so a British lake-village here and there defied progress till the coming of the Romans. There was one at Glastonbury, and its “Late Celtic” routine of life has been studied carefully from its remains.
Standing on an artificial island formed by a series of timber bridges, it occupied nearly three and a half acres, and its round huts, about sixty in number, were intermingled with a few square cabins that marked the most recent enterprise. Low walls were erected with upright posts driven into the artificial island at a distance of about a foot from each other; then this framework was wattled and plastered with clay. A few rough slabs of lias stone made a doorstep, a piece of timber lay across the threshold, a wood fire crackled on a central hearth, and every household wanted to feel entirely safe, for a tall and tight palisade enclosed the little colony. In this primitive defence a great many poles were set up side by side; they ranged in height from five to ten feet. Wolves and war were feared very much, evidently; and yet the villagers were devoted to that self-decoration with which men and women for many a long period had tried to rival the patterned colours given by Nature to birds, and beasts, and insects, and fish, and snakes, and flowers, and stones. They loved rings, cut from amber and jet and glass; wore bracelets, some of bronze, others of Kimmeridge shale; glass beads had their vogue, and clothes were fastened together with bronze safety-pins, or with split-ring brooches of bronze. Perhaps the women were truly feminine, and wore a monstrous headgear, outraging their good looks in fashionable efforts to renew their beauty.
Drawing closer to this village perched up on primitive bridges, we find in it some weavers and spinners, a few wood-carvers who were true artists, some carpenters who had lathes, and some clever smiths who made iron knives, awls, spades, bill-hooks, gouges; and a few ambitious potters decorated their work and gave it a careful finish. Harvests were grown somewhere, as women used querns to grind the corn. Good little people! They wanted to be pacific and artistic; fighting did not set their genius; and so they vanished. How could they hope to protect the gift of life when British war-chariots and Roman soldiers began to fight in the neighbourhood, obeying the dread mysterious law of fruitful carnage? They slunk away from the fierce midwifery of war, fearing the long self-sacrifices of a painful renaissance.
Their gentle enterprise lasted from about the second or third century B.C. to the Roman occupation. Among the remains of their village several skulls have been found, mild-looking skulls of a long shape, like those which have been taken from the long barrows. It was an Iberic tribe that trifled with peace and art, showing an epicene fervour akin to that of our cooing sentimentalists. Perhaps the Romans allowed the village to fade out of being, or perhaps they cleared it away as a futility, for neither Roman coins nor Roman wares have been found on the site, though remnants of Roman villas and potteries have been unburied in the vicinity.[49]
It is certain that most of the Roman bridges were built with timber. Thousands of trees were cut down when a paved road was constructed, so that cheap material for bridge-building was always at hand when the road was carried over ravines and rivers.[50] Besides, if a great many stone bridges had been built by the Romans, in Britain and elsewhere, many remains of the piers would have been found in all big rivers. We know, too, that the Romans were tolerant in their attitude to native bridgemen, since the criss-cross piers of the Gauls outlived the Roman Empire by many centuries.
We know not, neither can we learn, how the Romans themselves made timber bridges. Even their Pons Sublicius, a sacred monument, hallowed by historical traditions and by its connection with religious ceremonies, was described imperfectly. To this day experts quarrel over its technique and over its position on the Tiber. Colonel Emy has tried to reconstruct it, but his attempt differs from that of Canina, and we cannot choose between them. The utmost we can say is this--that the Pons Sublicius was a tree-bridge resting on piles, and dating from the times of Ancus Marcius, who reigned from B.C. 640-616. If the chief priests did not build it, they certainly kept it in repair, always using wood with a pious regard for a venerated past; and with their help it existed as late as the reign of Constantine (A.D. 306-337), when it was mentioned in the “Notitia,” and when a bridge was named after it at Constantinople. But the Pons Sublicius became obsolete as a highway for traffic, and then a good understudy bridge of stone--the Pons Lapideus--was built close at hand, and was known sometimes as Pons Sublicius, a title of honour. Sir William Smith believed that these bridges were outside the city, beyond the Porta Trigemina, and that the wooden one was built by Ancus Marcius in order to connect the town side of the Tiber with a new fortress erected on the Janiculus.
We pass on now to the brothers Grubenmann, whose best work was destroyed during the war of 1799. Ulric and Jean Grubenmann were village carpenters, born at Teufen, in the canton of Appenzell. Ulric seems to have been the abler of the two; certainly he was a man of true genius who spanned great distances by his unrivalled use of corbelled and trussed timber bearings. It was in 1755 that he began his suspension bridge at Schaffhausen, and in 1758 this work was complete. There were two spans in a distance of 364 feet, and they formed an elbow that pointed upstream. The abutment near Schaffhausen was 171 feet from the angle, and from the angle to the opposite shore was 193 feet. Ulric had decided that the bridge should cross the Rhine in one magnificent flight from abutment to abutment, but the town authorities interposed and told him to find use for a stone pier belonging to a bridge which a flood had ruined in 1754. Being a Swiss by birth and by training, Ulric Grubenmann followed an ancient tradition in Swiss carpentry, covering his bridge with a solid roof; and so perfect was the bridge, so admirably scarfed, trussed, strutted, braced, bolted up, and suspended, that only two faults could be found with it: the roof was too heavy, and the parts were too dependent on each other. An injury to one portion of the structure might have been disastrous to the whole bridge--a vital consideration in a warfaring time.
Grubenmann’s methods were simple. “The braces proceeding from each abutment,” said Telford, “are continued to the beam which passes along the top of the uprights, and the lowest of these general braces are actually united under that beam, thereby forming a continued arch between the abutments, the chord line of which is three hundred and sixty-four feet, and the versed sine about thirty feet. These braces are kept in a straight direction by the uprights, which are placed seventeen feet and five inches apart. If this bridge had been formed in a straight line between the abutments I can see no reason why this form of construction should not have supported a roadway of about eighteen feet in breadth, as well as a slight roof; because, in that case, all the weight arising from the braces which proceed from the middle pier would have been saved, and the roof might have been made much simpler and lighter.”
While Ulric Grubenmann was working at Schaffhausen, his brother Jean built a similar bridge at Reichenau, two hundred and forty feet in a single span; and some years later the two brothers constructed their Wittingen Bridge over the Limmat, near Baden, giving to it a span of three hundred and ninety feet. They were famous now, and their influence travelled from Europe to America, where it found in Bludget an able interpreter, Bludget’s bridge over the Portsmouth River being similar in technique to the bridge at Schaffhausen. Since that time the evolution of timber bridges has remained in the United States of America, where it has ranged from the criss-cross of logs for bearing piles to the most intricate combinations of lattices and trusses. Very often there is far too much intricacy, and no thought at all is given to military considerations (p. 352). “Many wooden American bridges are trusses which almost defy analysis, the designs being, however, obviously suggested by an attempt to combine at least two of the three main types of bridges. No advantage whatever is gained by a combination of this kind; on the contrary, great disadvantage is almost sure to follow its adoption, namely, that it will be impossible that each part of the structure should, under all circumstances, carry that portion of the load which the designer entrusted to it. For suppose a bridge constructed partly as a girder and partly as a suspension bridge, the girder being very stiff and deep, the chain perfectly flexible with considerable dip. Let the chain and girder be each fit to carry half the passing load. It is perfectly conceivable that the deflections of the two should be so different that the girder would, under the actual load, break before the chain was sensibly strained, or the difference in the relative dip of the chain and depth of the girder might be such as to cause the former to give way first.”[51]
VII
PRIMITIVE SUSPENSION BRIDGES
We have seen (p. 114) that the first suspension bridges were of two sorts: (_a_) long branches which had grown across rivulets and chasms; (_b_) thick and tough creeping plants by which many forest trees were festooned to one another. It is a vast evolution from these natural things to the art of Ulric Grubenmann, the forerunner of metal suspension bridges.[52] Unfortunately it is also an evolution which we cannot follow through many consecutive phases, artists and historians having failed to record its growth. We cannot suppose that the ancients neglected suspension bridges; from the spider alone they must have learnt that pendent ropes made a good bridge; but we know not what they achieved in this airy handicraft. Many people of to-day show in primitive hammock-bridges that their ancestors were influenced by the work of spiders. In countries so far apart as China and Central Africa and Northern India, for example, there are hammock-bridges of cane and osier, netted elaborately at the sides and swung by bamboo cables, as in China, or by ropes made from the silky fibres of the Nilgiri nettle, as in the Bermulda Hills. Whatever sort of primitive rope is employed, its first model was the gnarled and twisted stem of a vine-like creeping plant.
Perhaps the most ancient suspension bridge in China is the one known as _Liu Soh_ or _Lew saw_, literally a slip rope. A bamboo cable is fixed from side to side of a ravine, not in a level line, but a little aslant, so as to form a mild sort of switchback. A traveller carries a wooden saddle with a deep groove in it; the groove fits the bamboo cable, and straps fasten the saddle and give confidence to the jockey, who travels at a rapid speed when he is fat. On his return journey he is pulled up the bridge by ropes. In the mountains of Sichuan there are hundreds of these single cable-bridges.[53] What are they but lianes and vine stems _plus_ a little human primitiveness?
Don Antonio de Ulloa, the Spanish Admiral, describes a Peruvian bridge closely allied to the Chinese Liu Soh, and called the tarabita. Ulloa noticed it on several rivers, but particularly on the rapid Alchipichi. The tarabita is only a single rope made of bujuco, or ox-hide thongs twisted into a cable from six to eight inches in thickness. It is extended from one side of the river to the other, and anchored firmly. On one bankside it is controlled by a wheel, or winch, that makes it either taut or slack. A leather cradle is hung from the tarabita by two clasps that have rounded heads; two ropes are stretched across the river and bound to the travelling clasps; a wayfarer sits in the cradle and is pulled across by the guide-ropes. Even mules are slung from two tarabitas, according to Antonio de Ulloa, whose book on South America was published in 1748, at Madrid. An English translation appeared in 1758, and ran into five editions. Let me give a quotation from the fourth, issued in 1806. It concerns a venerable suspension bridge akin to the bamboo variety made in the mountains of Sichuan in China:--
“Over the river Desaguadero is still remaining the bridge of
rushes invented by Capac Yupanqui, the fifth Ynca, for
transporting his army to the other side, in order to conquer
the provinces of Collasuyo. The Desaguadero is here between
eighty and a hundred yards in breadth, flowing with a very
impetuous current under a smooth, and, as it were, a
sleeping surface. The Ynca, to overcome this difficulty,
ordered four very large cables to be made of a kind of grass
which covers the lofty heaths and mountains of that country,
and called Ichu by the Indians; and these cables were the
foundation of the whole structure. Two of them being laid
across the water, fascines of dry juncia and totora, species
of rushes, were fastened together, and laid across them. On
these the two other cables were laid, and covered with the
other fascines securely fixed, but smaller than the first,
and arranged in such a manner as to form a level surface;
and by this means he procured a safe passage for his army.
This bridge, which is about five yards in breadth, and one
and a half above the surface of the water, is carefully
repaired or rebuilt every six months, by the neighbouring
provinces, in pursuance of a law made by the Ynca (Capac
Yupanqui), and often since confirmed by the kings of
Spain.”[54]
In the first volume of his book, chap. VII., Antonio de Ulloa visits the Andes, and finds there some tree-bridges, some stone bridges, and some complex bujuco bridges. The stone variety he does not describe, but he writes interestingly about the bujucos. When six cables have been made by twisting together strips of ox-hide they are suspended across a river, not in a single row, but in two tiers, the lower one with four cables, the upper with two. Over the lower tier branches and canes are laid transversely; and when this floor is braced to the upper cables, there is a sort of cage within which travellers can walk in safety while the bridge swings.
“On some rivers of Peru,” says Ulloa, “there are bujuco bridges so large that droves of loaded mules pass over them; particularly over the river Apurimac, which is the thoroughfare of all the commerce carried on between Lima, Cusco, La Plata, and other parts to the southward.” Humboldt passed over one of these pendulous bridges, and Miers crossed another which was strong enough to bear the traffic of pack-mules, though it was two hundred and twenty-five feet in span.
And now we must pass on to a half-suspension bridge which is very common among the N’Komis, a tribe that inhabits the Fernan Vaz district in Equatorial Central Africa. It is a bridge built with Y-shaped sticks. Two parallel rows of these pronged branches are driven into the bed of a stream, and into the banksides; then long runners are put between the forks to bear a footway of sticks laid across them transversely.
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A book of bridgesChapter THE SECOND: Man as the MIMIC of Nature (1)
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