_Physical Factors Modifying the Formula of the Road: Marsh as the Chief
Obstacle to Travel: The Political Results of Marshes: The Crossing of
Water Courses: The Origin of the Bridge: The Effect of Bridges upon
Roads: The Creation of a Nodal Point: The Function of the Nodal Point
in History._
i
So much for the first principle of all: that the Road, like all other
human institutions, is best made with brains, and for that second
immensely valuable, but too often forgotten, political principle: that
if you begin by making your thing wrong it is likely to take root and
to remain wrong.
A catalogue of the more important physical factors modifying the
formula of the Road (I will come to the political and economic in a
moment) is as follows:
_Marsh to be traversed; water courses to be traversed; differences
of surface other than marsh and water courses; gradients to be dealt
with; the obstacle of vegetation to be dealt with._
To these five one may add a factor common to all, and to the making of
every road, even in its most primitive stages: (6) the proximity of
material (meaning by “proximity” the congeries of all the factors which
make for the cheapness of material, for the advantage of using it in a
particular place).
Let us take these physical points in their order.
* * * * *
ii
MARSH. It is not always appreciated that the chief obstacle to travel
from the beginning of time has been and still remains marsh, which
may be defined as soil too sodden for travel, as distinguished from
the lands which are boggy in wet weather but passable. Marsh is less
striking to the eye, especially to the modern eye, than a stretch of
water, much less striking than the apparent obstacle of the sea, or
of a bold hill range: it is nevertheless the chief problem presented
to the making of a road, because of all natural obstacles _it is
the only one wholly untraversable by unaided man_. Man unaided can
climb hills, swim water, work his way through dense undergrowth. But
marsh is _impassable_ to him: it is the great original obstacle to
progress. If this has not been recognized in the past, and is still
little recognized, it is not only because marsh is less striking to the
eye than water or hills, but still more because, the original roads
established by man in forming his cities, markets, and all the rest of
it, being compelled to avoid marsh, we do not often come across the
problem even to-day. Partly, also, because very extensive marsh is a
rare phenomenon, especially in Western Europe.
But if we look at the map and at history we shall see what that
obstacle means. It was marsh which cut off Lancashire from the South
of England, and left Lancashire the stronghold of old institutions,
especially after the Reformation. It was the marsh of the Lower Thames
estuary, now upon the right, now upon the left bank of the river,
which forbade a crossing below London. It was marsh which protected
the growth of Venice at the earliest and most dangerous moment of its
existence. It was marsh which cut off the Western (Polish) civilization
from the Eastern (Russian) civilization, and was the main geographical
cause of that sharp division in culture which has affected the whole
of later European history. We may say that the Russian Orthodox Church
and the last Revolution would neither have been, save for the Pinsk
Marshes. To take lesser examples, we can see to-day the way in which
even our modern ways avoid marsh. The large district of Gargano in
Southern Italy has remained largely isolated through marsh upon its
flanks.
You may see all over Europe, and even in this well-drained country,
primitive roads deflected through marsh as they are not by any other
obstacle, and this deflection stamps our road system to this day, in
spite of our enormously increased opportunities of road construction.
We shall see on a later page the way in which marsh deflected in the
dark ages Roman roads at the river crossings in this island.
If a special example be required of a road having grown up and remained
on an uneconomic trajectory on account of marsh moulding its earlier
history, one of the best in England is that of the Arundel road south
of Pulborough. Seawards from Pulborough (a landing and crossing-place
on the upper River Arun of great antiquity) the next considerable
inhabited spot was the port and fortified spur of Arundel. The distance
as the crow flies is a short day’s march or less, some ten miles. Now,
the road could have been taken in a fairly direct line and everywhere
upon the level had it not been for marsh. The marshes bordering the
Arun prevented such a construction in early times: the road had to keep
to a high, dry bank, then to climb right up to the top of the Downs and
fall again upon Arundel. So it remained--having taken root--through all
the advances in science: so it still stands to-day. The railway takes
the obvious line, but the road, established centuries ago, remains on
its former trajectory, climbs up many hundreds of feet, and then drops
down again to Arundel, involving in the short distance of ten miles
gradients of one in eight and heavy hill-climbing over more than half
the distance. A neighbouring example of the extreme importance of _the
first experiment_ in the history of a road is seen at Bramber, in the
next valley eastward. There a similar situation--the approach landwards
from the port of Shoreham--avoids the hills, because at some unknown
but very early period a causeway was built at Bramber to negotiate the
marsh; and that was because the isolated hill at Bramber afforded such
a good opportunity of fortification and blocking the pass that a road
was bound to reach it, and even under primitive conditions men were at
the labour of making an embankment.
[Illustration: Sketch II]
iii
WATER COURSES. The crossing of water courses does not seem to have been
originally _in the main_ a search for a ford. It seems to have been
rather a search for _good taking-off places upon either side, however
deep the water in between_. The ford was used, of course, wherever it
could be, and in it also the hardness of the passage under water was
of even more importance than the depth of water: below, say, 4 feet.
But the point to note is that often, and probably in the majority of
cases, man in the early times took his short cut across water either
by swimming or by taking advantage of floating material, and was much
more concerned with the hard bank upon either side than with the depth
of the stream.
If you take such a very old road as that of the primitive British
trackway whose two branches, from Stonehenge and Winchester, unite in
what is called the “Pilgrim’s Way” and make for the Straits of Dover,
you find this trackway crossing the Mole, the Wey, and the Medway, as
also the Darenth, at places where the obvious consideration has been
a dry approach upon either side, and not the local shallowness of the
stream. (We must remember in this connection that the word “ford” is
used at plenty of places where the stream is too deep for crossing on
foot: it means simply “a going.” A false etymology here has misled many
historians.) Of more importance to the first makers of the Road than
the depth of a water course was its swiftness. We have in this country
few examples of swift streams of any magnitude, and none of streams
so swift as to be impassable or passable with great difficulty, but
where such examples occur abroad it is easy to see what a boundary and
obstacle a rapid current afforded. It works in all manner of ways to
the disadvantage of travel, it makes both swimming and ferrying more
difficult (or impossible), it makes bridging either more difficult or
(in early times) impossible, it usually connotes great differences of
level, sudden floods, etc., and it also usually connotes changes and
variety of currents, as well as the destruction of the banks.
At an early stage in the development of the Road came the use of the
bridge, and with the bridge the original chief consideration--a dry
approach from either side--was emphasized. It is true that fords
were bridged as roads developed, but the bridging of a ford is not
the normal origin of the bridge. The normal origin of the bridge, if
we judge by any one of the original great roads of Europe, is the
replacing of a ferry. Men took the obstacle of a river (on account
of its length) as something hardly to be turned, save perhaps in its
higher reaches. They made straight for it, seeking only firm ground
from which to embark and disembark, and established a boat crossing. To
_this_ rather than to the ford the bridge succeeded. They bridged it
with increasing success as their material science increased in power,
and you may see all over Europe the great bridges thrown, not where the
river was shallowest nor where it was easiest to traverse for any other
reason, but chiefly where the main road led. In other words, the bridge
is a function of the Road rather than the Road of the bridge.
Two outstanding examples of this in Europe are London Bridge, perhaps
prehistoric, certainly not much less than two thousand years old, and
the bridge at Cologne, to which one might add the bridge at Rouen and
the bridges of the Island of Paris, which we know to be more than two
thousand years old. But it must be remembered that the bridging of a
river, even in primitive times, was the next easiest thing to a ferry,
and in some circumstances easier even than a ferry. A bridge need not
be built of piles. It may be built of boats, and in principle, even
over a broad stream, once you could build a boat bridge at all you
could build it of almost indefinite length. What would militate against
the effort to make a pile bridge were depth and rapidity of stream, but
even these, unless the rapidity were very great indeed, did not prevent
the throwing of a bridge of boats.
The bridge as an element in the Road plays a very large part which
needs some detailed examination: it develops a whole series of results.
The object of a bridge is to give _continuity_ and _security_ to travel
across an obstacle of depth: usually an obstacle of running water,
sometimes a dry ravine. _It is but rarely that a bridge is essential
to the mere trajectory of a road._ In much the greater number of cases
its function can be supplied, though far less perfectly, by a ferry, or
a ford, or a graded way down into and up from a depression. What the
bridge does is to permit of continued traffic, especially continued
wheeled traffic, across such obstacles without delay and without
trans-shipment, and at the same time to add, up to a maximum of weight,
to security; for it is obviously an instrument more secure than the
ferry or the ford, especially for heavy weights.
But the bridge has always represented a special economic effort,
greater yard for yard than that of the average of the road of which
it was a part; and that is why you almost always find it the mark of
civilization. A primitive culture can exist for centuries without
bridges. The proportion of bridge-building effort to road-building
effort varies very much with the physical science of various times. It
is less to-day, and was less in Roman times, than in primitive times
and in the Middle Ages, because we, like the Roman engineers, expend a
far greater economic effort upon the average of the Road, so that the
comparative cost of the bridge is less. In primitive times the bridge
was something of a feat, its construction as measured in effort was
equivalent to many miles of road, its builder a public benefactor, and
its building an event of note. This is so true that in some languages
which have come down but little changed from primitive times the word
for “bridge” is found to be a foreign word, as though the institution
were not sufficiently common before the advent of some civilized
conqueror to have acquired a special name; and in all primitive
societies the bridge is rare.
This comparatively high cost of the bridge has had certain effects on
the history and in the appearance of our roads which are worth noting.
In the first place, the bridge tends to be a “gut.” When the throwing
of a bridge was equivalent in expense to several miles of the existing
road it was a great saving to make it narrow: only one vehicle to pass
at a time, with side refuges at the piles when the passage of two
vehicles in opposing directions was unavoidable.
Again, bridges tended, especially in times of low economic development,
to introduce a sudden high gradient. The elliptical arch was, if not
unknown, at any rate very rare before the Renaissance, and where the
plain semi-circular arch alone was used a flat bridge involved, if the
crossing were of any width, a great number of piles, and therefore
an added expense. The difficulty was met in the majority of cases by
lessening the number of piles, especially towards the centre, where
there was a greater depth, consequently increasing the span there,
and consequently, in a semi-circular arch, increasing its height
correspondingly. The result was that the bridge introduced a sudden
hillock into the Road, and that feature you find all over Western
Europe up to quite modern times, with many survivals remaining,
especially in Spain. In some of the very early bridges in the poorer
districts, or on the less used roads, the exaggeration is fantastic. I
know of one over the Gallego, near Huesca, where the pitch is so steep
that it baulks a car.
There were particular structures--that of London is an example in
point--where the disadvantage of a gradient was avoided at great
expense because a mass of traffic and merchandise made it worth while.
London Bridge was carried on a great number of arches precisely in
order to avoid this element of gradient. A side-effect of this was the
blocking of the stream and great difficulty for boats in “shooting” the
arches on a tide; but this drawback to river traffic was thought worth
while as the price of a level road.
Another reason which often led to the expensive flat stone bridge was
its replacing an old wooden pile bridge. The wooden pile bridge had no
cause for creating a gradient. On the whole it was cheaper to keep it
exactly level, and as low as possible consistent with the rise of the
water. Where such a structure had preceded a stone bridge the habit
of a level road was continued, even at the expense of many piles and
arches.
A third effect of the bridge upon the Road, also due to its comparative
expense, was the convergence of roads towards bridges, established
or even only planned. You will perpetually find up and down Europe
the approaches to a town from two or more directions merged into
a common road just at the entry to a bridge, in order to save the
expense of two crossings, though at an extra expense of space and
time; thus, Abbeville, Caen (a very striking example, with _three_
converging roads on each side of the bridge), London--the chief example
in Europe--Saragossa, with the two main roads from south and west
converging on its bridge--all “gather” roads after this fashion.
But the effects of the bridge upon the mere trajectory of a road,
upon its surface and contour, were far less than were its political
and military effects. Though land armies were always tied to roads
more or less, it was possible to leave the road for short distances
under stress or for the sake of strategy. Cavalry continually did so
for great stretches, and infantry could do so occasionally. But a
bridge acted like a magnet. The defence of a bridge was the defence of
a point which an army in force was always compelled to use, and the
term “bridge head”--that is, the holding of the space on the _further_
side of the bridge, thus commanding the passage--is an example of its
permanent military function.
A bridge was, for the same reason, a natural place of toll.
Merchandise had to use it, and the same requirement of continual repair
which often entailed a permanent post at a bridge gave the opportunity
for using that post for the raising of taxation. All through the end
of the Roman Empire and the Dark and Middle Ages this function of the
bridge is most prominent.
iv
But most important of all the effects of the bridge is its creation
of a _nodal point_, that is, a knot or crossing of ways. The bridge
effects this in two fashions: firstly by that tendency to a convergence
of roads upon the bridge which I have just noted, and secondly, and
much more important, by the transverse of the bridge and the river. A
river is also a high road if it is in any way navigable. Therefore,
wherever a land road crosses a river and establishes a bridge you get
a crossways of communications. At such a point, where many avenues of
approach meet, and whence opportunities of travel to different places
radiate, you have what is called in political geography a Nodal Point.
[Illustration: ICKNIELD STREET in the Oxfordshire Chilterns]
Now, the nodal point is of such importance that it merits particular
attention. The nodal point, especially if it is established by a
bridge, has two great functions in history. It determines the strategy
of campaigns (and alters even the tactics of actions), it determines
the growth of towns. It has been said that London was made by its
bridge. Whether there was a settlement (there probably was) upon the
gravelly hill which approached the river from the north, before any
bridge was thrown across the tidal Thames, we do not know; but it is
certain that the throwing of this bridge gave London its opportunity
for development, and what is true of London is true of Paris, of Rouen,
of Maestricht, of Cologne, and of twenty other great urban centres in
our civilization. Strategically, a commander holding a nodal point
retains the opportunity of moving along any one of many lines of
movement, and at the same time denies the opportunity of junction to
his enemies. To put it in its simplest form, a commander holding a
nodal point and concentrated there can prevent the concentration of two
fractions of his enemy along any two roads radiating from that nodal
point. He can himself march up each of these consecutively and defeat
the two fractions of his enemy in detail. That is the simplest possible
case, and it can be developed into any amount of detail and intricacy.
The bridge is the point where the commerce up and down stream crosses
the road-commerce transversely to the river-commerce, and the nodal
point of the bridge establishes a market. But that nodal point has
other characters even more important to civilian life. It creates a
point of _trans-shipment_, where goods must be transferred from the
water vehicle to the land vehicle. In their transference you have the
political opportunity of examination and toll, and, if necessary,
interception; and you also have, of course, the whole of the middleman
business of dealing with and passing through the goods--you have the
depot and the warehousing and all the adjuncts of a built-up commercial
centre and a market.
But the bridge as a nodal point has yet another occasional function
which has marked all history. That function it exercises when it is the
lowest bridge upon a great navigable river. Such a bridge--the bridge
of Rome for instance, the bridge of London, the bridge of Gloucester,
the bridge of Newcastle, etc.--has been the making of inland ports. It
must be remembered that before the advent of the railway, or at any
rate before the organization of rapid and easy road travel, it was to
the interest of sea-borne trade to penetrate into the heart of the
country as far as possible. You avoided the cost of trans-shipment,
and you had a much cheaper means of conveyance than anything that went
by land. But the first permanent bridge across a waterway blocked the
further progress up-stream of sea-borne traffic. Therefore there was a
tendency to keep this first bridge well up-stream. Further, whenever
it was made, it tended to create a glut of traffic at this point of
section. The cargoes from the sea came here and could go no further,
and this last function of the bridge is perhaps of all its historical
functions the most important. Even where a river is very rapid, as the
Tiber, the first bridge has some effect. Where it is tidal it is, of
course, as in the cases we have just quoted, of the greatest effect,
and usually on the great tidal waterways the first bridge will be
found not indeed at the limit of the tide, for there the water would
be too shallow, but in the last reaches. There are cases (Rochester is
one) where the road has proved more important than the stream, where
a bridge was imposed very low down in the tideway, but it has there
fulfilled the same function of creating a market and a town. There
are cases (Antwerp, Bordeaux, and Philadelphia are examples) where
a secure harbour and good wharfage made the inland market and town
in the absence of such an obstacle as the first bridge; but in the
greater number of navigable rivers, even in so narrow a stream as that
of Seville, the bridge makes the port and the town, as one can see by
adding to the examples already given Nantes, Montreuil, Glasgow, etc.
There is a little note on the crossing of water courses which is
curious and interesting in the history of roads. Since the crossing
is always an effort, or, in economic terms, an expense, to be avoided
as much as possible, the Road naturally avoids a _double crossing_,
but, on the other hand, an island is a stronghold, and even a peninsula
where two rivers meet is a potential stronghold. Therefore you have in
the history of all early European roads a sort of dilemma, the first
travellers debating, as it were, whether the occasion were sufficiently
important to warrant the double crossing of the stream. At Reading,
Lyons, Melun, notably at Paris, and in dozens of other places, the
presence of the stronghold made it worth while for the Road to visit
the place in spite of the double crossing, whether to an island or to
the meeting of two streams. But in much the majority of cases the Road
was deflected from its simplest line to a point below the meeting of
two streams so as to avoid the double effort, and the occasion explains
many a deflection which otherwise would seem to have no reason.