Next morning when they arrived at the New Sea they found that the wind came more down the water, having turned a little to the south, but it was the same in force. They started again, and sailed very well till they were opposite the hollow oak in which on the day of battle it was supposed Bevis had hidden. Here the wind was a head-wind, against which they could only work by tacking, and when they came to tack they found just the same difficulty as yesterday. All the space they gained during the tack was lost in coming round before the boat could get way on her. They sailed to and fro from the hollow oak to some willow bushes on the other side, and could not advance farther. Sometimes they got above the oak, but then they fell back behind the willow bushes; sometimes they worked up twenty yards higher than the willow bushes, but dropped below the oak. Bevis soon discovered why they made better tacks now and then; it was because the wind shifted a little, and did not so directly oppose them. The instant it returned to its usual course they could not progress up the sea. By the willow bushes they could partly see into Fir-Tree Gulf; yesterday they could not sail out of the gulf, and to-day, with all their efforts, they could not sail into it. After about twenty trials they were compelled to own that they were beaten, and returned to harbour. Bevis was very much troubled with this failure, and as soon as they had got home he asked Mark to go up in the bench-room, or do anything he liked, and leave him by himself while he looked at the old encyclopaedia. Mark did as he was asked, knowing that Bevis always learnt anything best by himself. Bevis went up into the bedroom, where the great book remained open on the chair, knelt down, and set to work to read everything there was in it on ships and navigation. There was the whole history of boats and ships, from the papyrus canoes of the Nile, made by plaiting the stalks, the earthenware boats, hide boats, rafts or skins, hollowed trees, bark canoes, catamarans, and proas. There was an account of the triremes of Rome, and on down to the caravels, bilanders, galliots, zebecs, and great three-deckers. The book did not quite reach to the days of glorious Nelson. It laid down the course supposed to have been followed by Ulysses, and described the voyages of the Phoenicians to Britain. The parts of a three-decker were pictured, and the instruments of navigation were explained with illustrations. Everything was there except what Bevis wanted, for in all this exhaustive and really interesting treatise, there were no plain directions how to tack.