The last adventure recorded of Merlin proceeded from a project he conceived for surrounding his native town of Caermarthen with a brazen wall. He committed the execution of this project to a multitude of fiends, who laboured upon the plan underground in a neighbouring cavern. [150] In the mean while Merlin had become enamoured of a supernatural being, called the Lady of the Lake. The lady had long resisted his importunities, and in fact had no inclination to yield to his suit. One day however she sent for him in great haste; and Merlin was of course eager to comply with her invitation. Nevertheless, before he set out, he gave it strictly in charge to the fiends, that they should by no means suspend their labours till they saw him return. The design of the lady was to make sport with him, and elude his addresses. Merlin on the contrary, with the hope to melt her severity, undertook to shew her the wonders of his art. Among the rest he exhibited to her observation a tomb, formed to contain two bodies; at the same time teaching her a charm, by means of which the sepulchre would close, and never again be opened. The lady pretended not to believe that the tomb was wide enough for its purpose, and inveigled the credulous Merlin to enter it, and place himself as one dead. No sooner had she so far succeeded, than she closed the lid of the sepulchre, and pronouncing the charm, rendered it impossible that it should ever be opened again till the day of judgment. Thus, according to the story, Merlin was shut in, a corrupted and putrifying body with a living soul, to which still inhered the faculty of returning in audible sounds a prophetic answer to such as resorted to it as an oracle. Meanwhile the fiends, at work in the cavern near Caermarthen, mindful of the injunction of their taskmaster, not to suspend their labours till his return, proceed for ever in their office; and the traveller who passes that way, if he lays his ear close to the mouth of the cavern, may hear a ghastly noise of iron chains and brazen caldrons, the loud strokes of the hammer, and the ringing sound of the anvil, intermixed with the pants and groans of the workmen, enough to unsettle the brain and confound the faculties of him that for any time shall listen to the din.