At this juncture an untoward event occurred, in the re-taking by the Americans of the brig _Detroit_, formerly the United States brig _Adams_--captured, as we know, by Roulette--and the trading brig _Caledonia_. They were at anchor at the head of the Niagara River, off Black Rock. The irregular regiments of Hull's command, under the terms of surrender, were on board on their way to their Ohio homes, via Lake Erie and Buffalo. The two vessels reached Fort Erie harbour safely, and being rightly regarded by the British as immune from attack, were left undefended, in charge of an officer and nine men only, most of whom were voyageurs. In addition to the prisoners, the two brigs carried great quantities of fur and 600 packs of deer skins. During darkness Lieutenant Ellis, with three armed boats and 150 United States troops and sailors, dropped alongside. Roulette and his nine men fought desperately, one being killed and four wounded, but both vessels, of course, fell into the enemy's hands. This attack was contrary to the rules of war, and a violation of the sanctity of the flag which "continued to float as long as there were American prisoners on board, awaiting to be landed on United States soil." Brock regarded this loss as a calamity. It was, he wrote to Prevost, "likely to reduce him to great distress." His constant fears that the enemy would secure control of both Lakes Erie and Ontario were well founded. He begged Prevost to let him destroy the vessels Chauncey, the American, was building on Squaw Island. Prevost, of course, besought him to forbear. Isaac Brock, exasperated and with tied hands, was "doomed to the bitterest of all griefs, to see clearly and yet be able to do nothing." Yet while he worked in chains his preparedness was a source of wonder to those behind the scenes. Even no less a critic than John Lovett, General Van Rensselaer's military secretary, was impressed with what he saw through his field-glasses from Lewiston heights. "Every three or four miles, on every eminence," he wrote a friend, "Brock has erected a snug battery, the last saucy argument of kings, poking their white noses and round black nostrils right upon your face, ready to spit fire and brimstone in your very teeth, if you were to offer to turn squatter on John Bull's land." Influenced by these signs of "business," the United States officers were ordered to "dress as much like their men as possible, so that at 150 yards they might not be recognized." This was probably due to one of the last orders issued by our hero, who warned his men that, when the enemy crossed the river, to withhold their musketry fire until he was well within range, and then, "if he lands, attack him at the point of the bayonet with determined resolution."