The Hôtel de Nesle, on the side bounded by the Pré-aux-Clercs, was doubly defended by its walls and by the city moat, so that on that side it was considered impregnable. Now Ascanio very sensibly reflected that it is seldom deemed necessary to guard what cannot be taken, and he determined to make an attack upon the point where the besieged had not thought of providing against one. With that object in view he set out with his friend Jacques Aubry, not dreaming that, as he disappeared in one direction, Colombe would appear in the other, and provide Benvenuto with a means of compelling the provost to adopt a course which he was most reluctant to adopt. Ascanio's scheme was very difficult of execution, and very dangerous in its possible results. He proposed to cross a deep moat, scale a wall twenty-five feet high, and at the end perhaps fall into the midst of the enemy. Not till he arrived at the brink of the moat and of his enterprise did he realize the difficulty of crossing the one and carrying through the other; and then his determination, firm as it was at the outset, wavered for an instant. Jacques Aubry halted some ten or twelve paces behind his friend, and stood tranquilly gazing from the wall to the moat. Having measured them both with his eye, he said:-- "I beg you, my dear fellow, to have the kindness to inform me why you bring me hither, unless it be to fish for frogs. Ah! yes,--you glance at your ladder. Very good. I understand. But your ladder is only twelve feet long, while the wall is twenty-five feet high and the moat ten wide, which makes a difference of twenty-three feet, if my reckoning is correct." Ascanio was taken aback for a moment by this unanswerable arithmetic; but suddenly he cried, striking his forehead with his hand:-- "Ah! I have an idea! Look!" "Where?" "There!" said Ascanio; "there!" "That's not an idea you are pointing at," rejoined the student, "but an oak tree." There was in truth a huge oak growing near the outer edge of the moat, the upper branches of which gazed inquisitively over the wall of the Séjour de Nesle. "What? don't you understand?" cried Ascanio. "Yes! yes! I begin to see through it now. Yes, it's the very thing. I see it all. The oak and the wall form part of the arch of a bridge which your ladder will complete: but the abyss yawns beneath, my friend, and an abyss full of mud. The devil! we mustn't forget that. I am wearing my best clothes, and Simonne's husband is beginning to grumble about giving me credit." "Help me to hoist the ladder," said Ascanio; "that's all I ask of you." "Aha!" said the student, "and I am to stay below! Thanks!"