The commonest type of the barrier-frontier was a palisade or mound or rampart or wall; elsewhere use might be made of an existing road or canal or ditch. Of the latter class a familiar illustration is the great Roman road of Watling Street, in this country, which, by the Treaty between Alfred and Guthrum, was made the boundary between the English territories and the Danes. An early English example of the other type was Offa's Dyke, the huge earthwork constructed by the Mercian king of that name (about 780 A.D.) from the mouth of the Wye to the mouth of the Dee as a Frontier against the Welsh. Palisades have been found as far apart as the borders of China and Manchuria and of Manchuria and Korea, and the outskirts of the Roman dominions beyond the Danube and the Rhine. Spartianus, in his Life of Hadrian [7] describes the palisade erected by that Emperor in the trans-Danubian section of the Roman Frontier, and the researches of the German explorers, who in recent years have laid bare the traces of that remarkable barricade from end to end, have revealed the existence of split oak trunks, nine feet high, driven into a deep ditch, and held together by stout transverse beams.
The palisade or rampart or wall of ancient history was, however, the commonest illustration of a type of Frontier that was concerned less with delimitation than with defence. When the Chinese built the Great Wall of China, when Hadrian and Antoninus Pius and Severus raised the double line of fortification between the Firths of Clyde and Forth, and between the Solway and the mouth of the Tyne, when the Flavian Emperors built the Pfahlgraben and other ramparts or walls between the Rhine and the Danube, when the successors of Alexander raised a similar barrier in the country to the east of the Caspian - one and all were not thinking so much of rounding off the territories of conquests of the Empire as they were of protecting its Frontiers in the best manner against the terrible and ever-swelling menace of the barbarians. Consequently the wall or barrier was sometimes erected upon the administrative Frontier, and sometimes far in advance of it. Though Hadrian's wall was for centuries the effective Frontier of the Roman dominion in Britain, the Romans yet to some extent occupied the ground between it and the second or northern wall, and even beyond the latter. Similarly the Roman 'limes' in what is now Germany and Austria advanced or receded, not so much as indicating a fluctuating movement of the real boundaries of the Empire, as following the best line of military defence that was suggested by the exigencies of the time. Trajan's conquest of Dacia was of course a positive, though only a temporary, extension of the Empire.
Rudimentary in conception though these structural barriers may be thought to have been, they were effective in the age and against the foes for whom they were devised. There can be no greater mistake than to ridicule them as monuments of misdirected effort or of human vanity. The Great Wall of China, commenced before the Christian Era and continued at intervals for 1,700 years, was a genuine palladium to the heart of the Chinese Empire. Though occasionally circumvented and more than once pierced by the nomad hordes, for centuries it held back the Mongolian Tartars from Peking, acting as a fiscal barrier for the prevention of smuggling and the levying of dues, as a police barrier for the examination of passports and the arrest of criminals or suspects, and as a military barrier against hostile invasions or raids. It was even more a line of trespass than a Frontier. Much the same might be said of the Roman walls, whether directed against the Picts and Scots, or against the Marcomanni and Teutonic tribes. Guarded by fortified posts or forts at intervals, with watch-towers between, garrisoned in the early days of the Roman Empire by veterans of the army, in later times by native auxiliaries, with the great legionary camps in the rear, they kept the front of the Empire until the ever-mounting crest of the barbarian torrent burst through defences, which there were no longer the men or the military spirit to defend. Walls and ramparts have now passed away as Frontiers of dominions, just as they are becoming obsolete as defences of cities. Occasionally in some remote corner to which the tides of human movement have not penetrated, their survivals are found. The Tibetans thought that they could bar their mountain plateaux to the Indian army by a stone wall built across a valley. A more practical and modern analogy has been traced in the Customs Hedge or Frontier made of thorny bushes and trees, which until a few years ago was stretched for 2,500 miles round the territories of British India to keep out contraband salt from the Native States [8].
But a commoner and more widely diffused type of ancient Frontier was that of the intermediary or Neutral Zone. This may be described as a Frontier of separation in place of contact, a line whose distinguishing feature is that it possesses breadth as well as length. Sometimes it was a razed or depopulated or devastated tract of country; at others a debatable strip between the territories of rival powers: or, again, a border territory subject to and defended by one party, though exposed to the ravages of the other. Between Korea and China there existed, till beyond the middle of the last century, a broad uncultivated and uninhabited tract over 5,000 square miles in extent in which neither people were permitted to settle under penalty of death (though latterly it began to be encroached upon by colonists from both sides), and which became an Alsatia for roving banditti. A more innocent reproduction of the same idea may still be seen in the Neutral Ground between the British and Spanish Lines at Gibraltar. Travellers have reported the existence of the same device for keeping apart the lands of tribal communities in Central Africa, in the interior regions of the Soudan, the Congo, and the Niger.
In mediaeval times we see a more developed form of the same expedient in the Marks or Marches - a part of the settled policy of Charlemagne and Otto, and generally of the Frankish and German kings. From these Marks, intended to safeguard the Frontiers of the Empire from Slavonic or alien contact, and ruled by Markgrafs or Margraves, sprang nearly all the kingdoms and States which afterwards obtained an independent national existence, until they became either the seats of empires themselves, as in the case of the Mark of Brandenburg, or autonomous members of the German Federation. The same word (already familiar in the Marcomanni or Marchmen of the days of Antoninus), and in slightly different forms the same practice, reappear in the West Saxon kingdom of Mercia, or the March-land, in the Marches between England and Wales, for five centuries the scene of bloody conflicts between the Marcher Lords or delegates of the English kings, and the Welsh inhabitants; in the title Marquis, springing from that office; in the Wardens of the Marches, three on the English and three on the Scottish border, who watched each other from both sides of the Tweed and the Cheviots, and interwove a woof of chivalry and high romance into a warp of merciless rapine and savage deeds; and, finally, in the title of the Merse given to the Lowland counties on the Scottish side of the border. I would that I had the time to say something here about that typical illustration of Frontier character and Frontier civilization, whose history is written in the battered castles and peels of the Border, and enshrined in a literature of inimitable charm.
More pertinent is it to notice that from this ancient and mediaeval conception of a neutral strip or belt of severance has sprung the modern idea of a deliberately neutralized territory, or state, or zone. The object in both cases is the same, viz. to keep apart two Powers whose contact might provoke collision: but the modus operandi is different. Where primitive communities began by creating a desert in order to prevent occupation, and then provided for occupation by authorities and forces specially deputed for the purpose, modern States construct their buffer by diplomatic conventions, and seek the accommodating sanction of International Law. At one end of these devices we are but little removed from primitive practice. I allude to the arbitrary and often anomalous creation by modern powers of small neutral zones, ostensibly with a view of avoiding contact, quite as frequently in order to evade some diplomatic difficulty or to furnish material for future claims. Of such a character was the 25-kilometre strip on the right bank of the Mekong created by the Franco-Siamese Treaty of 1893, nominally owned but not policed by Siam, containing both authorities and inhabitants whose connexion lay with the opposite or French bank. Such a diplomatic fiction could only be a temporary expedient preluding a more effective solution. Similar in character and result were the neutral zone established by Great Britain and Germany in the Hinterland of the Gold Coast in 1888, and the petty buffer State which Lord Rosebery sought to erect in 1893-5 between the borders of India and of France on the Upper Mekong. The abortive Agreements of 1894 with King Leopold and the Congo State were similarly intended to set up a buffer between the Central African territories of Great Britain and her European rivals. A yet further illustration would be the Cis-Sutlej strip of territory, into which, though it belonged to the Sikh rulers, they were not permitted by treaty to enter with armed force, and their violation of which led to the Sikh wars. Of these artificial expedients it may be laid down that they have no durability, unless they are based upon some intelligible principle of construction or defined by a defensible line, and are administered by an authority capable of preserving order [9].
The history of British, and subsequently of American, expansion in America affords a significant illustration of the futility of an artificial buffer. When the British had conquered Canada and all the territories east of the Mississippi, George III issued a Proclamation (Oct., I763) forbidding settlements beyond the sources of the rivers flowing into the Atlantic (this was known as the 'fall line'), reserving the lands beyond the Alleghanies for the Indians, and forbidding settlers to enter them. At the same time an effort was made to construct a buffer along the Indian border by the purchase of Indian lands and the settlement of European colonists upon them. But the Alleghanies were crossed almost before the ink on the Proclamation was dry; and, these once passed, no other physical barrier intervened until the Great Plains and the Rocky Mountains, which retarded, but did not finally impede, the American advance to the Pacific [10]. The Americans inherited the British policy, and as they pushed forward kept steadily thrusting the Indian Frontier backwards by a series of removals or deportations, the object being in each case to separate them from contact with the white man. But the progress of the latter was so rapid that these artificial Frontiers were continually being caught up and overlapped, the Indian territories finding themselves enveloped in the advancing tide. This led to the 'reservation' system, which continues to this day, and under which the national existence of the Indians is only, and that with difficulty, preserved by the creation of 'enclaves' with arbitrary Frontiers.
Much more is to be said for the buffer State as commonly understood, i.e. the country possessing a national existence of its own, which is fortified by the territorial and political guarantee, either of the two Powers between whose dominions it lies and by whom it would otherwise inevitably be crushed, or of a number of great Powers interested in the preservation of the status quo. The valley of the Menam, which is the central portion of Siam, has been thus guaranteed by Great Britain and France; Abyssinia has been guaranteed by these two Powers and Italy: in the Agreement just concluded between Great Britain and Russia about Central Asia the integrity and independence of Persia are once more guaranteed by the two great contracting parties - thereby constituting that country a true buffer State between their respective dominions: but a new provision is introduced in which, while rival spheres of interest, Russian and British, are created on the north and east respectively, a zone is left between them of equal opportunity to both Powers. This is an arrangement wanting both in expediency and permanence, the more so as the so-called neutral zone is carved exclusively out of the regions in which British interests have hitherto been and ought to remain supreme. The same Agreement contains a further novelty in international diplomacy, in the shape of a neutralizing pledge about Tibet made by two Powers, one of which is contiguous while the other has no territorial contact whatever with that country. Tibet is not a buffer State between Great Britain and Russia; the sequel of the recent expedition has merely been to make it again what it had latterly ceased to be, namely, a Mark or Frontier Protectorate of the Chinese Empire. There is a second type of buffer State lying between two great Powers in which the predominant political influence is acknowledged to belong to one of the two and not to the other. Korea, which has passed under the unchallenged influence of Japan, is such a buffer State between Japan and China. Afghanistan is in the same position between Great Britain and Russia. Here we have a close analogy to the Mark system of the Frankish Emperors and to the practice of the Roman Empire, which sought to protect its Frontiers by a fringe of dependent kingdoms, or client-states.
In all these cases the buffer State is an expedient more or less artificial, according to the degree of stability which its government and institutions may enjoy, constructed in order to keep apart the Frontiers of converging Powers. That such an experiment must necessarily fail is certainly not the teaching of European history, where it is the marchlands of Empire, Castile, France, Prussia, that have often fought their way to greatness and fame. A quite abnormal type of a buffer State existed in Europe, with slight breaks, for over 1,100 years, in the shape of the Papal Dominions. Its boundaries were perpetually shifting, and they made no pretense to represent natural or geographical lines of division. But they approximately severed the continental and peninsular portions of Italy, those parts which have always looked to the West, and those parts which have constantly been exposed to Hellenic or Eastern influences.
In Europe, however, buffer States have not as a general rule been situated between the territories of Powers possessing superior force and a higher civilization. In Asia, where the experiment is now more commonly tried, and where the conditions are less favourable, the degree of vitality to be expected is less. There the buffer conditions are apt to foster intrigue outside, apathy and often anarchy within; and either partition follows or the stronger and least scrupulous of the bordering Powers absorbs the whole. It is unlikely that Korea will permanently retain even her present figment of independence. The future of Siam, Persia, and Afghanistan constitutes one of those problems on which speculation on an occasion like the present would be at once improper and unwise.
Lastly, there are the States, situated entirely in Europe, which are protected by an International Guarantee. These are, Switzerland neutralized by eight Powers in 18I5, Belgium neutralized by five Powers in 1831, and Luxemburg neutralized by five Powers in 1867, the object in each case having been to create a buffer State between Germany and France [11]. Neutralization does not absolutely protect, and has in practice not protected, these countries from violation: but it renders aggression less likely by making it an international issue. The desire to extend a Frontier at the expense of a neutralized State can, therefore, only be gratified at a rather expensive price. Whether Holland, and the Scandinavian kingdoms, can permanently retain their independence without the safeguard of some such form of guarantee is problematical. The former has to some extent protected itself by constituting the Hague the seat of an International Tribunal, which claims to be interested in the preservation of peace: the latter are temporarily safeguarded by dynastic alliances. But in both groups lie critical Frontier issues of the future.
I now proceed to the examination of the commoner forms of Artificial Frontiers in use among modern States. These are three in number: (1) what may be described as the pure astronomical Frontier, following a parallel of latitude or a meridian of longitude; (2) a mathematical line connecting two points, the astronomical coordinates of which are specified; and (3) a Frontier defined by reference to some existing and, as a rule, artificial feature or condition. Their common characteristic is that they are, as a rule, adopted for purposes of political convenience, that they are indifferent to physical or ethnological features, and that they are applied in new countries where the rights of communities or tribes have not been stereotyped, and where it is possible to deal in a rough and ready manner with unexplored and often uninhabited tracks. They are rarely found in Europe, or even in Asia, where either long settlement or conflict has, as a rule, resulted in boundaries of another type.
(1) The best known illustration of the astronomical line is the Frontier between Canada and the United States, which from the Lake of the Woods follows the 49th parallel of latitude to the Pacific coast, a distance of 1,800 miles. This line well illustrates both the strength and the weakness of the system. As a conventional line through unknown territories it has answered its purpose. But its demarcation on the spot was so laborious and protracted that, fifty years after the conclusion of the Treaty which created it, the joint surveyors were still at work, clearing a strip 100 yards wide through the primaeval forest, and ornamenting it with iron pillars and cairns, at a cost to both countries which was enormous. Similar lines have been employed to define the boundaries of Canada and Alaska, to separate many of the Australian Colonies from each other, to determine European Spheres of Influence or Protectorates in Africa, and, quite recently, to define the Russian and Japanese shares of the island of Saghalin. Such lines are very tempting to diplomatists, who in the happy irresponsibility of their office-chairs think nothing of intersecting rivers, lakes, and mountains, or of severing communities and tribes. But even in the most favourable circumstances they require an arduous triangulation on the spot, and until surveyed, located, and marked out, have no local or topographical value.
(2) The straight line from point to point is also a method very popular in America, where it has been employed in laying down the internal Frontiers of States, and is in keeping with the mathematical precision commonly applied to the laying out of cities and streets. Like the Frontiers of latitude or longitude this type of boundary is a useful and sometimes an indispensable expedient; but it possesses no elasticity, and it is apt to produce absurd and irrational results. It is said in America that many men reside in one State and do their business in another, and there is no reason why so artificial a device should not have even more inconvenient consequences. The internal administrative or county boundaries of Great Britain have been constructed on the opposite principle, and represent a combination of historical, geographical, and occasionally ethnological conditions.
(3) Frontiers by reference, i.e. Frontiers defined as running in a specified direction or for a certain distance, or as the arc of a circle, or as the tangent to a circle, are very familiar features in African treaties, where use hasto be made of visible features or landmarks. But they are a fruitful source of error or misunderstanding, both in terminology and topography. For instance, the Alaskan dispute between Canada and the United States turned upon the meaning of the ambiguous words 'a line parallel to the windings of the coast which shall never exceed the distance of ten marine leagues therefrom'. What was the coast referred to, and what was the practicability or meaning of a line that scaled inaccessible peaks and was lost amid ice and eternal snow?
I have now passed in review the various forms of Frontiers either furnished by nature or created by man, and have endeavoured to indicate their degrees of strength or weakness. In practice the tendency of mankind has been to ignore or override nature, and in the case of older States to adopt racial or linguistic or purely political lines of division, in the case of the partition of new countries to adopt the temporary or conditional expedients which have been described. In North America few of the internal boundaries correspond to any natural feature. In South America where, owing to the configuration and history of the country, natural boundaries are commoner, there is scarcely an undisputed Frontier. In Europe, apart from certain ranges of mountains, (but few rivers), which being genuine barriers have exercised a permanent influence upon the formation of States and the distribution of men, the boundaries of the majority of States are purely political, and find their origin in the events of history; although geographical conditions, such as the eligibility of elevated, or sterile, or sparsely peopled tracts for Frontier purposes, have not been without influence in their selection. Of political or historical Frontiers I may mention as illustrations the Frontiers of Spain and Portugal, of Germany and Holland, of Germany and Austria, of Russia and Germany, of France and Germany (except the Vosges), of France and Belgium, of Belgium and Holland, of Turkey and Greece. Here and there exists a State like Switzerland, which accords with no one principle of national distribution, or Belgium, which infringes them all. Both are the creations of expediency or of fear. In Asiatic Frontier delineations tribal boundaries, except where overridden by political considerations, are apt to be observed.