It is a delusion to imagine that a plan of campaign can be laid down far ahead and fulfilled with exactitude. The first collision with the enemy creates a new situation in accordance with its result. Some things intended will have become impracticable; others, which originally seemed impossible, become feasible. All that the leader of an army can do is to form a correct estimate of the circumstances, to decide for the best for the moment, and carry out his purpose unflinchingly.
The advance of the French troops to the frontier, while as yet imperfectly mobilized, which was an extremely hazardous measure in itself, was evidently with the intent of utilizing the temporary advantage of having a superior force at immediate disposition by taking at unawares the German armies in the act of developing their advance-movements. But, notwithstanding, the German commanders did not deviate from their purpose of promptly effecting this first advance in front of the Rhine. The railway transport of the Corps of the IInd and IIIrd Armies, however, ended at the Rhine; thence the troops marched on foot into the cantonments prepared on the left bank of the river. They moved in echelon, advancing only so many at a time as would make room for the body in rear, in the first instance to the line Bingen-Dürkheim-Landau. The farther advance towards the frontier was not to be undertaken until the Divisions and Corps were all assembled, and provided with the necessary trains; and then they were to march forward in a state of readiness to confront the enemy at any moment.
The massing of the Ist Army appeared to be less threatened, because its route was protected by neutral territory, and was covered by the garrisons of Trèves, Saarlouis and Saarbrücken, the German outposts on the Saar.
The Ist Army, 50,000 strong, was concentrated at Wadern, in the first days of August. The IInd Army, which meanwhile had been increased to a strength of 194,000 men, had pushed forward its cantonments to Alsenz-Günnstadt, at the farther base of the Haardt Mountains, a position which had been thoroughly inspected by an officer of the General Staff, and where the troops might confidently await an attack. The 5th and 6th cavalry Divisions were reconnoitring the country in front. The IIIrd Army was still assembling on both banks of the Rhine.