e bulk
of the expedition, however, had already crossed to the right bank
of the river; Caesar followed them and in twenty-four hours effected
the passage, which the unwieldy host of the Helvetii had not been able
to accomplish in twenty days. The Helvetii, prevented by this passage
of the river on the part of the Roman army from continuing
their march westward, turned in a northerly direction, doubtless
under the supposition that Caesar would not venture to follow them
far into the interior of Gaul, and with the intention, if he should
desist from following them, of turning again toward their proper
destination. For fifteen days the Roman army marched behind
that of the enemy at a distance of about four miles, clinging
to its rear, and hoping for an advantageous opportunity of assailing
the Helvetic host under conditions favourable to victory,
and destroying it. But this moment came not: unwieldy as was the march
of the Helvetic caravan, the leaders knew how to guard against
a surprise, and appeared to be copiously provided with supplies
as well as most accurately informed by their spies of every event
in the Roman camp. On the other hand the Romans began to suffer
from want of necessaries, especially when the Helvetii removed
from the Saone and the means of river-transport ceased. The non-arrival
of the supplies promised by the Haedui, from which this embarrassment
primarily arose, excited the more suspicion, as both armies
were still moving about in their territory. Moreover the considerable
Roman cavalry, numbering almost 4000 horse, proved utterly
untrustworthy--which doubtless admitted of explanation,
for they consisted almost wholly of Celtic horsemen, especially
of the mounted retainers of the Haedui, under the command of Dumnorix
the well-known enemy of the Romans, and Caesar himself had taken
them over still more as hostages than as soldiers. There was good
reason to believe that a defeat which they suffered at the hands
of the far weaker Helvetic cavalry was occasioned by themselves,
and that the enemy was informed by them of all occurrences
in the Roman camp. The position of Caesar grew critical; it was
becoming disagreeably evident, how much the Celtic patriot party
could effect even with the Haedui in spite of their official
alliance with Rome, and of the distinctive interests of this canton
inclining it towards the Romans; what was to be the issue, if they
ventured deeper and deeper into a country