It seems tolerably certain that, when the battle began again next day, William's army numbered between forty-five and fifty thousand, with the usual proportion of cavalry,--probably a tenth of the whole. James, on the other hand, had from twenty to twenty-five thousand men, about a tenth of them, probably, being mounted; he had, by his own fault, only six guns against about fifty in William's batteries. William's line of battle was formed, as usual, with the infantry in the center and the cavalry on the wings. He gave the elder Schomberg command of the center, while Schomberg's son, with the cavalry of the right wing, was sent four or five miles up the river to Slane, to cross there and turn the left flank of the opposing army. William himself led the cavalry on the left wing, and later on in the battle, descending the river, crossed at a lower ford. He could thus attack the right flank of his opponent; the infantry composing the center of his army advancing, meanwhile, under cover of a heavy artillery fire, and forcing the fords of the Boyne. The river is shallow here, and in the middle of summer the water is nowhere too deep for wading, so that it was a very slight protection to the army of James. A better general would at least have chosen a stronger position, and one which would have given him some manifest advantage. Such positions were to be found all along the road by which William had advanced from Carrickfergus. The country on both sides of the Boyne is flat; rolling meadows with the shallow river dividing them--a country giving every opportunity to cavalry. William's right, under the younger Schomberg, made several unsuccessful attempts to cross the river at Slane, being repeatedly beaten back by Arthur O'Neill's horse. Finally, however, the way was cleared for him by a vigorous cannonade, to which O'Neill, having no cannon, was unable to reply, and William's right wing thus forced the passage of the Boyne.