The brewery fortunately turned the course of Forester's thoughts, and, instead of quarrelling with his friend for being tired, he condescended to postpone all further debate. Forester had, from his childhood, a habit of twirling a key, whenever he was thinking intently: the key had been produced, and had been twirling upon its accustomed thumb during the argument upon address; and it was still in Forester's hand when they went into the brewery. As he looked and listened, the key was essential to his power of attending; at length, as he stopped to view a large brewing vat, the key unluckily slipped from his thumb, and fell to the bottom of the vat: it was so deep, that the tinkling sound of the key, as it touched the bottom, was scarcely heard. A young man who belonged to the brewery immediately descended by a ladder into the vat, to get the key, but scarcely had he reached the bottom, when he fell down senseless. Henry Campbell was speaking to one of the clerks of the brewery when this accident happened: a man came running to them with the news, "The vat has not been cleaned; it's full of bad air." "Draw him up, let down a hook and cords for him instantly, or he's a dead man," cried Henry, and he instantly ran to the place. What was his terror, when he beheld Forester descending the ladder! He called to him to stop; he assured him that the man could be saved without his hazarding his life: but Forester persisted; he had one end of a cord in his hand, which he said he could fasten in an instant round the man's body. There was a skylight nearly over the vat, so that the light fell directly upon the bottom. Henry saw his friend reach the last step of the ladder. As Forester stooped to put the rope round the shoulders of the man, who lay insensible at the bottom of the vat, a sudden air of idiocy came over his animated countenance; his limbs seemed no longer to obey his will; his arms dropped, and he fell insensible. The spectators, who were looking down from above, were so much terrified, that they could not decide to do any thing; some cried, "It's all over with him! Why would he go down?" Others ran to procure a hook--others called to him to take up the rope again, if he possibly could: but Forester could not hear or understand them, Henry Campbell was the only person who, in this scene of danger and confusion, had sufficient presence of mind to be of service. Near the large vat, into which Forester had descended, there was a cistern of cold water. Henry seized a bucket, which was floating in the cistern, filled it with water, and emptied the water into the vat, dashing it against the sides, to disperse the water, and to displace the mephitic air{4}, He called to the people, who surrounded him, for assistance; the water expelled the air; and, when it was safe to descend, Henry instantly went down the ladder himself, and fastened the cord round Forester, who was quite helpless. {Footnote 4: Carbonic acid gas.}