This done, he moved to one side, and standing at a distance of about ten feet from the slab, pulled at the chain which lay upon it, and which, as Forrester now saw, was fastened to a stout ring in its upper edge. The slab moved on hinges slowly towards the Chinaman, and as it rose from the floor, a shaft of pale green light, blinding in its brilliance, shot up to the roof, fourteen or fifteen feet above, causing the two Englishmen to start back and retreat some paces into the passage. Forrester was conscious of an intensification of his nervous excitement. His ears buzzed; his skin tingled as if he were in an electric bath; his impulse was to cover his eyes and rush headlong to escape the terrible glare and its psychical accompaniment. But seeing Beresford venturing back by degrees, he exerted his will to the utmost, and followed him.
A shaft of pale green light, blinding in its brilliance, shot up to the roof.
The Chinaman, who was probably at the outset less nervously organised than they, and was certainly inured to the conditions, was carefully paying out the chain over the wheel, with its weighted plate, into a hole in the floor. As Forrester now perceived, the two chains were one, which was much longer than had appeared when it was coiled up. When it was stretched to its full length, it rose vertically from the slab to the bar, ran through hooks in this for a few feet, then descended perpendicularly over the wheel. The Chinaman drew back, and leant against the wall in the relaxed attitude of one waiting. To the Englishmen, in this overpowering atmosphere, the period of inaction seemed an hour: it was really about five minutes. Then the Chinaman approached the chain, taking care to remain as far as possible from the hole, and with careful deliberateness hauled it in, moving backward as he did so. Forrester waited with feverish impatience as it clinked inch by inch over the wheel. When at last the square plate came to the top, the Chinaman raised it until there was room for the slab to pass beneath it, and prevented it from slipping down over the wheel by hooking the chain to the wall, leaving, however, the greater part of the chain free.
Then, with a quickness all the more surprising because of his slow movements hitherto, he rushed with bent head at the slab, gave it one vigorous push, and darted back to the wall, catching at the chain in time to prevent the slab from falling violently. When it was settled in its place, and the blinding glare was shut off, the old man sank on the floor as if to rest after tremendous exertions.
At first Forrester felt a dull disappointment. Without a definite expectation, he had anticipated some striking phenomenon as the result of this elaborate performance. The plate, whose upper surface was towards him, seemed after its long descent to be exactly as it was before: there was no change in it, nor had it brought anything up from the pit into which it had been plunged. But after a few minutes had passed, the Chinaman turned it over, and Forrester was mildly surprised to perceive that the under surface had changed its colour. It was now greenish yellow, like the chain, the bar, and all the other parts of the machinery. In his half-dazed condition he did not suspect the extraordinary character of the transformation.
The Chinaman having reversed the plate, fastened it again to the chain, and went through the same series of careful movements as before. During the second period of waiting, Forrester, prompted by his companion, followed with his eyes the vertical path of the shaft of light from the hole to the roof. He noticed there an aperture, corresponding in size to the hole. A little fine dust was falling from this aperture, like soot from a chimney, into and around the opening of the pit, the minute particles dancing and glistening like the motes in a sunbeam.
When the plate came up the second time, its colour was the same on both sides. The Chinaman unhooked it, carried it across the cavern into the recess, and reappeared with a similar plate, dull and lustreless as the first had been.
Beresford drew Forrester away, and hurried him back through the passage, saying nothing until they regained the larger cavern. Then he halted, clutched the lapels of Forrester's coat, and said:--
"Well, what do you think of that?"