Alsace, for he was still following the course of the Rhine.
Once he diverged from the valley of this river and struck across the bend
of the Neckar to the south and east, the alternative he had chosen of
making the Upper Danube the seat of war was apparent.

It is therefore at this point in his advance that we must consider the art
by which he had put the enemy in suspense, and confused their judgment of
his design.

The first point in the problem for a modern reader to appreciate is the
average rate at which news would travel at that time and in that place. A
very important dispatch could cover a hundred miles and more in the day
with special organisation for its delivery, and with the certitude that it
had gone from one particular place to another particular place. But
general daily information as to the movements of a moving enemy could not
be so organised.

We must take it that the French commanders upon the left bank of the Rhine
at Landau, or upon the Meuse (where Villeroy was when Marlborough began
his march), would require full forty-eight hours to be informed of the
objective of each new move.

For instance, on the 25th of May Marlborough's forces were approaching
Coblentz. To find out what they were going to do next, the French would
have to know whether they were beginning to turn up the valley of the
Moselle, which begins at Coblentz, or to cross that river and be going on
further south. A messenger might have been certain that the latter was
their intention by midday of the 26th, but Tallard, right away on the
Upper Rhine, would hardly have known this before the morning of the 29th,
and by the morning of the 29th Marlborough was already opposite Mayence.

It is this gap of from one to three days in the passage of information
which is so difficult for a modern man to seize, and which yet made
possible all Marlborough's manoeuvres to confuse the French.

Villeroy was bound to watch until, at least, the 29th of May for the
chance of a campaign upon the Moselle.

Meanwhile, Tallard was not only far off in the valley of the Upper Rhine,
but occupied in a remarkable operation which, had he not subsequently
suffered defeat at Blenheim, would have left him a high reputation as a
general.

This operation was the reinforcement of the army under the Elector of
Bavaria and Marcin by a dash right through the enemy's country in the
Black Forest.

Early in May the Elector of Bavaria had urgently demanded reinfo