Colonel Duff of the 88th regiment had such misgivings as to the result of the day that he left the colours of his regiment behind him with the reserve, and, when he advanced before dawn to the head of the street by which he was to enter the city, he found his regiment so weak that he sent back for two of the companies which had been left with the reserve. Before these companies were allowed to join him they were ordered to take the flints from their muskets and leave them behind, and Colonel Duff lost much time in trying to provide them with flints, by searching among the rest of his men for spare ones. Even so, many of the men of these two companies entered into action without flints. The division under the command of Colonel Mahon, which advanced from Quilmes to the Puente Galvès on the 5th July, consisted of about 1800 men, infantry, artillery and dismounted cavalry, the 9th and 17th Light Dragoons, and 200 sailors from the squadron, who had been landed by Admiral Murray to assist in dragging the cannon through the swamps at Ensenada, where five guns captured from the Spaniards at Monte Video stuck fast and were destroyed by Colonel Frazer. The idea of General Whitelock appears to have been, that by avoiding the main streets of the city, which led direct from the Corrales to the Plaza Mayor, and by a rapid march before sunrise, without firing, through the suburbs and shorter streets, he would succeed in surprising the principal positions to the north and south of the great square, which idea, considering that most of these positions were a league distant from the Plaza Miserere, presumed a great want of vigilance on the part of the garrison, while all chance of a surprise was effectually destroyed by the way in which the signal to advance was given. As the day dawned a salvo of twenty-one British guns on the Plaza Miserere gave the signal. The troops marched at once; each subdivision in column of sections, seven men in line, left its position and disappeared down the muddy roads, hedged by aloe fences, which led through the suburbs. They disappeared, marching along avenues in which they could see nothing either to the right hand or to the left, towards an unknown goal at the end of a long, narrow path shrouded in darkness and in mist. Liniers had made every preparation for a vigorous defence. Including the regular troops, the three battalions of Patricios, the Arribeño regiment, armed citizens, slaves,[6] and the dismounted paisanos, he had over 15,000 men under his command. The regular troops were concentrated about the defences of the Plaza Mayor, but the militia were spread about on the azoteas all over the city.