The plans of these two great generals were extremely simple. The object of the Duke of Wellington was to maintain his line of defence, until the Prussians coming up, should give him a decided superiority of force. They were expected about eleven or twelve o'clock; but the extreme badness of the roads, owing to the violence of the storm, detained them several hours later. Napoleon's scheme was equally plain and decided. He trusted by his usual rapidity of attack, to break and destroy the British army before the Prussians should arrive in the field; after which, he calculated to have an opportunity of destroying the Prussians, by attacking them on their march through the broken ground interposed betwixt them and the British. In these expectations he was the more confident, that he believed Grouchy's force, detached on the 17th in pursuit of Blucher, was sufficient to retard, if not altogether to check, the march of the Prussians. His grounds for entertaining this latter opinion, were, as we shall afterwards show, too hastily adopted. Commencing the action according to his usual system, Napoleon kept his guard in reserve, in order to take opportunity of charging with them, when repeated attacks of column after column, and squadron after squadron, should induce his wearied enemy to show some symptoms of irresolution. But Napoleon's movements were not very rapid. His army had suffered by the storm even more than the English, who were in bivouac at three in the afternoon of the 17th June; while the French were still under march, and could not get into line on the heights of La Belle Alliance until ten or eleven o'clock of the 18th. The English army had thus some leisure to take food, and to prepare their arms before the action; and Napoleon lost several hours ere he could commence the attack. Time was, indeed, inestimably precious for both parties, and hours, nay, minutes, were of importance. But of this Napoleon was less aware than was the Duke of Wellington.