The Allied artillery, on the left bank of the Parana, kept up a heavy fire upon the post of Itapirú. But there was nothing there to receive any damage, the 12-pounder being snugly stowed away for an occasion. This continued for some time; until, at last, the Brazilians occupied a sand bank, or bar, in the river, opposite Itapirú, and mounted eight guns there, with two thousand men in trenches. From this point they reopened a fire upon the work, which seemed a perfect bugbear to them. On the 10th of April the Paraguayans attacked this bank, or bar; and the naval part of the enterprise consisted in their coming in canoes. Nine hundred men were embarked, in divisions of four hundred and fifty each; with a reserve of four hundred at Itapirú. It was a dark night, and the canoes, propelled by paddles, arrived at the bank, or bar, at four o’clock in the morning. It was a complete surprise; and the Paraguayans delivered one volley, and then charged with the bayonet, taking the trenches. They were soon driven out of them again, however, by overwhelming numbers; retook them, and were again driven out. The Brazilian guns opened with canister, and the Paraguayans lost heavily from this source. Two hundred of them were dismounted cavalrymen, armed only with their swords, but they did great execution, charging up to the guns, and taking them; but being again driven off by heavy musketry fire. As soon as the firing was heard below several gunboats and ironclads came up, and surrounded the island, while the garrison was reinforced from the left bank. At last the Paraguayans were almost all killed or wounded, and those who could move pushed off in their canoes, some paddling with one arm who had the other one wounded. The daylight had appeared, and they were forced to stem a heavy current, under the fire of the Brazilian vessels, at close quarters; and yet fifteen canoes got back to their own shore. The Paraguayans lost fourteen officers killed, and seven wounded. Of the soldiers three hundred returned, almost all wounded, and they left five hundred men on the bank, or bar. Among the prisoners taken by the Brazilians was a Lieutenant Roméro; and Lopez forced his wife to write a letter disowning him as a traitor to Paraguay, because he had allowed himself to be taken alive. In this affair the Brazilians lost about a thousand, killed and wounded, many more than the whole attacking force. The fire of their own steamers destroyed a number of these. Six Brazilians were afterwards tried for cowardice in this engagement, and were shot. In February, 1868, the Brazilian iron-clad vessels succeeded in passing Humáitá, the extensive works above the confluence of the rivers, which had so long kept them in check.