Dr Prudhom trembled too, but his agitation was unfeigned. The three stood still breathless, and watched the dim figure as it hovered across their path, and then vanished into the darkness. "What can it be?" said the doctor, bracing himself up with an effort, and preparing to walk on. "Oh, please, sir," cried the boys, "don't go on! do let us turn back! Oh dear! oh dear!" "Foolish boys!" said the doctor; "haven't you sense enough to know that no such thing as--ah! there it is again!" Yes, there it was again. A faint beam of the moon broke through the clouds, and lit up the white figure once more where it stood close to the sign-post. And as they watched it seemed to grow, rising higher and higher till its head nearly touched the cross-bars. Then suddenly, and with a groan, it seemed to drop into the earth, and all was darkness once more. The boys clung one on each side to the doctor, who trembled hardly less than themselves. No one dared move, or speak, or utter a sound. Again the moon sent forth a beam, as the figure once more appeared and slowly rose higher and higher. For a moment it seemed as if it would soar into the air, but again with a dull crash it descended and vanished. "Boys," said the doctor hoarsely, "I confess I--I am puzzled!" "I--I wonder," said Dell, "if I ever dare go and see what it is. I say, M-m-organ, would you g-g-go with me--for the d-d-doctor's sake?" "Oh, Dell! I'm afraid. But--yes, I'll try." "Brave boys!" said the doctor, never taking his eyes off the spot where the ghost last vanished. The two boys stole forward on tiptoe, holding one another's arms; then suddenly they broke into a rush straight for the sign-post. There was a loud shriek as the white figure rose up to meet them. "Bilk, you idiot, cut back for your life! here's the doctor! We were only having a lark with you. Do cut your sticks, and slip in quietly, and it'll be all right. Look alive, or we're all three done for!" The ill-starred Bilk needed no further invitation. He started to run as fast as his long legs would carry him, his night-gown flapping in the evening breeze, and his two persecutors following him with cries of "Booh!" "Scat!" "Shoo!" and other formulae for exorcising evil spirits. After a hundred yards or so the two heroes gave up the chase, and returned to the slowly-reviving doctor. "Come along, sir," said Dell; "there's nothing there; it vanished as soon as we got to it. Let us be quick, sir, in case it comes back." The remainder of the walk home that evening, I need hardly observe, was brisk; but it was not so brisk as the same journey accomplished by Alexander Magnus Bilk, who had reached the school a full quarter of an hour before his pursuers, and was safe between his blankets by the time that they peeped into his room on their way to bed, and whispered consolingly, "It's all up with the duke's daughter now, old man!"