Every stroke of the oars was now made with infinite precaution, and the boat crawled along at a snail’s pace. Pepito, in the bow, leant over to watch for the boom which blocked the waterway, and many times dipped his hands into the icy-cold water so that touch might not fail where sight was impossible. The air was raw and chilly, and Jack was delighted to learn, from his sensations in throat and eyes, that the mist of which his informant had spoken was an actuality. It was drawing towards dawn. The darkness was yielding to a faint luminance that was not yet light, when suddenly, a few moments after Pepito had withdrawn his numbed hand from the water, the boat was pulled up with a jolt, and a harsh prolonged creak testified that its nose had come at last into contact with the boom—a heavy chain drawn across the river from bank to bank. Instantly there was a cry from the bank on their right: "Qui va la?" At that same moment, without the least hesitation, Pepito slipped noiselessly over the side of the boat into the water, caught the chain with one hand, and endeavoured to pull it down, whispering to his master to row over. But his puny strength was, of course, unavailing, and he crept back shivering into the bows. Jack, however, had at once divined the only possible solution of the problem. So heavy a chain must undoubtedly sag towards the middle of the stream. Was the middle to his right hand or his left? He pulled the boat sideways against the obstruction, and told Pepito to slip overboard and walk along the chain while he himself gently paddled. At a guess he moved to the right, and was soon gratified by Pepito’s whispered announcement that the chain seemed to be sinking. When the water reached the boy’s middle, Jack gently brought the boat’s head to the stream, and with two vigorous strokes drove the unwieldy vessel across the boom. The boat’s bottom scraped the massive links as it crossed; Pepito clambered in rather too hastily and slipped; the sounds caught the ears of the sentry on the bank, and another cry of "Qui va la?" penetrated the mist, followed by a shot. More voices were heard; more shots; and then from a point behind came the sound of a boat being run down the bank. Jack now plied his oars with might and main; cries, followed by shots, rang out from the other bank, and then, ahead and approaching him, he heard the straining of oars against rowlocks. There was no time for hesitation. Pulling hard on the left oar he headed for the bank, taking his chance, and in a few seconds grounded with a shock. In an instant he was out of the boat, and, followed closely by Pepito, started at a quick walk through the clinging fog in what he guessed must be the direction of the city.