an army consists in a great body of human beings, artificially gathered together under conditions which do not permit of men supplying their own wants by agriculture or other forms of labour. They are gathered together for the principal purpose of fighting. They must be fed; they must be provided with ammunition, usually with shelter and with firing, and if possible with remounts for their cavalry; reinforcements for every branch of their service must be able to reach them along known and friendly (or well-defended) roads, called their lines of communication. These must proceed from some base, that is from some secure place in which stores of men and material can be accumulated.
Next, it is important to notice that variations in speed between two opposed forces will nearly always put the slow at a disadvantage in the face of the more prompt. For just as in boxing the quicker man can stop one blow and get another in where the slower man would fail, or just as in football the faster runner can head off the man with the ball, so in war superior mobility is a fixed factor of advantage—but a factor far more serious than it is in any game. The force which moves most quickly can “walk round” its opponent, can choose its field for action, can strike in flank, can escape, can effect a junction where the slower force would fail.
It is these two causes, then—the artificial character of an army, with its vast numbers collected in one place and dependent for existence upon the labour of others and the supreme importance of rapidity—which between them render obstacles that seem indifferent to a civilian in time of peace so formidable to a General upon the march.
The heavy train, the artillery, the provisioning of the force, can in general only proceed upon good ways or by navigable rivers. At any rate, if the army departs from these, a rival army in possession of such means of progress will have the supreme advantage of mobility.
Again, upon the flat an army may proceed by many parallel roads, and thus in a number of comparatively short columns, marching upon one front towards a common rendezvous. But in hilly country it will be confined to certain defiles, sometimes very few, often reduced to one practicable pass. There is no possibility of an advance by many routes in short columns, each in touch with its neighbours; the whole advance resolves itself into one interminable file.
Now, in proportion to the length of a column, the units of which must each march one directly behind the other, do the mechanical difficulties of conducting such a column increase. Every accident or shock in the long line is aggravated in proportion to the length of the line. Finally, a force thus drawn out on the march in one exiguous and lengthy trail is in the worst possible disposition for meeting an attack delivered upon it from either side.
All this, which is true of the actual march of the army, is equally true of its power to maintain its supply over a line of hills (to take that example of an obstacle); and therefore a line of hills, especially if these hills be confused and steep, and especially if they be provided with but bad roads across them, will dangerously isolate an army whose general base lies upon the further side of them.
What the reader has just read explains the peculiar character which the valley of the Upper Danube has always had in the history of Western European war.
The Rhine and its tributaries form one great system of communications, diversified, indeed, by many local accidents of hill and marsh and forest, with which, for the purposes of this study, we need not concern ourselves.
In a lesser degree, the upper valley of the Danube and its tributaries, though these are largely in the nature of mountain torrents, forms another system of communications, nourishing considerable towns, drawing upon which communications, and relying upon which towns as centres of supply, an army may manœuvre.
But between the system of the Rhine and that of the Danube there runs a long sweep of very broken country, the Black Forest merging into the Swabian Jura, which in a military sense cuts off the one basin from the other.
At the opening of the eighteenth century, when that great stretch of hills had but a score of roads, none of them well kept up, when no town of any importance could be found in their valleys, and when no communication, even of a verbal message, could proceed faster than a mounted man, this sweep of hills was a very formidable obstacle indeed.
It was these hills, when Marlborough determined to strike across them, and to engage himself in the valley of the Upper Danube, which formed the chief physical factor of his hazard; for, once engaged in them, still more when he had crossed them, his appeals for aid, his reception of advice, perhaps eventually a reinforcement of men or supplies, must depend upon the Rhine valley.
True he had, the one within a week of the Danube, the other within two days of it, the couple of depots mentioned above, the principal one at Nuremberg, the advanced one at Nordlingen. Nevertheless, so long as he was upon the further or eastern side of the hills, his position would remain one of great risk, unless, indeed, or until, he had had the good fortune to destroy the forces of the enemy.
All this being before the reader, the progress of the great march may now be briefly described.
In the winter between 1703 and 1704 domestic irritation and home intrigues, with which we are not here concerned, almost persuaded Marlborough to give up his great rôle upon the Continent of Europe.
Luckily for the alliance against Louis and for the history of British arms, he returned upon this determination or phantasy, and with the very beginning of the year began his plans for the coming campaign.
He crossed first to Holland in the middle of January 1704, persuaded the Dutch Government to grant a subsidy to the German troops in the South, pretended (since he knew how nervous the Dutch would be if they heard of the plan for withdrawing a great army from their frontiers to the Danube) that he intended operating upon the Moselle, returned to England, saw with the utmost activity to the raising of recruits and to the domestic organisation of the expedition, and reached Holland again to undertake the most famous action of his life in the latter part of April.
It was upon the 5th of May that he left the Hague. He was at Maestricht till the 14th, superintending every detail and ordering the construction of bridges over the Meuse by which the advance was to begin. Upon the 16th he left by the southward road for Bedburg, and immediately his army broke winter quarters for the great march.
It was upon the 18th of May that the British regiments marched out of Ruremonde by the bridges constructed over the Meuse, aiming for the rendezvous at Bedburg.
The very beginning of the march was disturbed by the fears of the Dutch and of others, though Marlborough had carefully kept secret the design of marching to the Danube, and though all imagined that the valley of the Moselle was his objective.
Marlborough quieted these fears, and was in a better position to insist from the fact that he claimed control over the very large force which was directly in the pay of England.
He struck for the Rhine, up the valley of which he would receive further contingents, supplied by the minor members of the Grand Alliance, as he marched.
By the 23rd he was at Bonn with the cavalry, his brother Churchill following with the infantry. Thence the heavy baggage and the artillery proceeded by water up the river to Coblentz, and when Coblentz was reached (upon the 25th of May) it was apparent that the Moselle at least was not his objective, for on the next day, the 26th, he crossed both that river and the Rhine with his army, and continued his march up the right bank of the Rhine.
But this did not mean that he might not still intend to carry the war into Alsace. He was at Cassel, opposite Mayence, three days after leaving Coblentz; four days later the head of the column had reached the Neckar at Ladenberg, where bridges had already been built by Marlborough’s orders, and upon the 3rd of June the troops crossed over to the further bank.
Here was the decisive junction where Marlborough must show his hand: the first few miles of his progress south-eastward across the bend of the Neckar would make it clear that his object was not Alsace, but the Danube.
He had announced to the Dutch and all Europe an attack upon the valley of the Moselle; that this was a ruse all could see when he passed Coblentz without turning up the valley of that river. The whole week following, and until he reached the Neckar, it