Next day we all went back to our work. We began first to shape the outside of the canoe--a task we performed with our axes, and at this four could work at once. By Jack's advice we planed off the upper side of the tree, so that the plan of the canoe could be drawn off on it by exact measurements. We first drew a straight line down the centre, and from this measured off the two sides with the greatest care. In the game way the stem and stern were measured with a plumb-line. We then turned the log over, and having levelled that side, marked off the keel, thus having it truly in the centre. Natty and Leo had remained to assist in turning over the log. "Why, that is exactly how I should cut out a model-boat!" exclaimed Leo. "If we had a saw we could shape the bows and stern much more easily, just as I always used to do." "But you see, young gentleman, we must make use of what tools we have," observed Jack. "By sticking at it, I dare say we shall not be as long cutting out this here canoe as you would have been making a little model." "Let me see," said Leo. "No; I remember it took me a good month before I got it ready for painting, and even then, I own, from some unaccountable cause, it was somewhat lopsided." "Maybe you did not use the plumb-line, Master Leo," observed Jack. "You see there is nothing like that for getting things perpendicular, though I cannot say exactly the reason why." "There I have you, Jack, then," said Leo. "It is on account of the centre of gravitation, and a weight let down on the earth always falls perpendicularly to the plane of the earth." "That may be philosophy, as you call it, Master Leo, but I cannot say as how I am much wiser than I was; only you will see we will get our canoe to sit fairly on the water--neither heeling over to one side nor t'other." Having got all our measurements correct, we once more put the canoe on an even keel, and then commenced chopping away round the intended gunwale, so as to have the upper works done first. By Jack's advice she was sharp at both ends, like a whale-boat, that we might the better back out of danger if necessary. "Come, you are getting on so fast with the canoe, that we shall not have the spars ready if we do not set to work," said Natty. "Come along, Leo;" and the boys ran off with their axes on their shoulders in high glee. They had not been gone long when we heard their voices crying out, "Come, come!--quick, quick!" Stanley, David, and I hurried on with our guns, which we kept ready for use, and soon reached the boys. They were too excited at first to speak. "A wild man!" cried Leo. "A fierce-looking fellow! I thought he was going to run after us, but he did not, and I do not know if he is still there." "But was he a wild man?" said Natty. "He was walking along on all fours, and then he went up a tree. If he had been a man I do not think he would have done that." "Probably he was a big ape," said David; "another gorilla."