This danger of the union of the two allied armies was, as the Bertrand order shows, distinctly recognized as a possible danger by Napoleon when he dictated the order to Bertrand. It is true that Napoleon did not think it likely that this union would be made, but he knew perfectly well that if it should be made, it would place him in the greatest peril. He, therefore, expressly warned Grouchy that the Prussians might be intending to unite with the English to fight another battle for the defence of Brussels; and we have seen that, in the event of Grouchy’s finding this to be the case, Napoleon expected him to cross the Dyle and act in conjunction with the main army. If this was, in Napoleon’s opinion, to be his true course in the not impossible event of Blücher’s falling back on Wavre, why send him off at all? What was there to be gained by sending him off which made it worth while to run the risks inseparable from detaching such a large force from the main army when such a terrible danger as the union of the Prussian and English armies was even remotely apprehended? For there certainly was a chance of Grouchy’s not coming back in time to prevent the catastrophe; Napoleon ran the risk of Grouchy’s not receiving accurate or trustworthy information as to the doings of the enemy,—of his not acting on the information which he might obtain in accordance with sound military principles,—of his being delayed by the destruction of the bridges, and by the manœuvres of the enemy. But this is not all. If the Prussians had fallen back on Wavre with the intention of uniting with the English and fighting another battle for the defence of Brussels, as Napoleon in the Bertrand order warns Grouchy they might be intending to do, they must have carried out their project in great part at the time when Napoleon was dictating his order to Bertrand. On this hypothesis, they had certainly already obtained a great advantage over any force sent to pursue them or to interrupt the execution of their scheme. Was it not therefore much wiser to keep the whole army together, well in hand, and under the Emperor’s immediate direction? These risks and chances, and others, Napoleon took, when he sent Grouchy off with his 33,000 men; and for what? The fact probably is this; that Grouchy was originally ordered to follow up and observe the Prussians when every one supposed them to be retreating towards the Rhine, and especially to prevent or check any offensive return upon the French communications; and that when Napoleon, between 12 and 1, received information which awakened in his mind doubts of the correctness of this supposition, and even some apprehension that Blücher might be intending to unite with Wellington and fight another battle for the defence of Brussels, he adhered to his original disposition of Grouchy’s force, contenting himself with giving him an express warning of the danger to be apprehended. The question then comes down to this:—