He obeyed, without demur.
His father passed him, and he heard him walking through the damp grass outside the door of the barn. There followed an intolerable interval. From some place, not very distant, he could hear Dr. Cairn moving, hear the chink of glass upon glass, as though he were pouring out something from a stoppered bottle. Then a faint acrid smell was wafted to his nostrils, perceptible even above the heavy odour of the incense from the barn.
"Relock the door!" came the cry.
Robert Cairn reclosed the door, snapped the padlock fast, and began to fumble with the skeleton keys with which they had come provided. He discovered that to reclose the padlock was quite as difficult as to open it. His hands were trembling too; he was all anxiety to see what had taken place behind him. So that when at last a sharp click told of the task accomplished, he turned in a flash and saw his father placing tufts of grass upon a charred patch from which a faint haze of smoke still arose. He walked over and joined him.
"What have you done, sir?"
"I have robbed him of his armour," replied the doctor, grimly. His face was very pale, his eyes were very bright. "I have destroyed the Book of Thoth!"
"Then, he will be unable—"
"He will still be able to summon his dreadful servant, Rob. Having summoned him once, he can summon him again, but—"
"Well, sir?"
"He cannot control him."