The Black Hole of Glenranald
sented it next day in office hours," replied the manager. "But it's too late to think about it now, and in a few days Donkin may know the truth."
He might have known it already, but for one difficulty. They had digged their pit to the generous depth of eight feet, so that a tall prisoner could barely touch the trap-door with extended fingertips; and Stingaree (whose latest performance was no longer the Yallarook affair) was of medium height according to his police description. The trap-door was a double one, which parted in the centre with the deadly precision of the gallows floor. The difficulty was to make the flaps close automatically, with the mouse-trap effect of Macbean's ambition. It was managed eventually by boring separate wells for a weight behind the hinges on either side. Copper wire running on minute pulleys let into grooves suspended these weights and connected them with the flaps, and powerful door-springs supplemented the more elaborate contrivance. The lever controlling the whole was concealed under the counter, and reached by thrusting a foot through a panel, which also opened inward on a spring.
It may be conceived that all this represented the midnight labors and the constant thought of many weeks. It was now the beginning of the cool but
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