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THE BRITISH ISLES. 



plugged up, to prevent its irruption. The noise of rolling pebbles and of the surf 

 becomes terrific wben we penetrate this mine, and on a tempestuous day the uproar 

 is sufficient to cause even the hardiest miner to shudder. Elsewhere the old 

 miners had the imprudence to follow a lode within so short a distance of the bed 

 of the sea, that the latter broke through the roof of the mine and flooded a portion 

 of its galleries. The hole, however, was fortunately stopped up by means of a 

 plank platform covered with turf and weighted with stones. Another copper mine 

 to the south of Penzance is often cited as an instance of the enterprise of the 

 Cornish miners. It was commenced towards the close of the last century by a work- 

 Fig. 44. — The Bot.\llack Mine. 



ing miner, on a part of the beach which was covered twice daily by the advancing 

 tide. Under these circumstances it was only possible to work for a few hours of the 

 day. But when the mine had been enclosed by a wooden fence and joined to the 

 land by a plank bridge, it became possible to work it continuously, and for a 

 number of years the " Wherry " yielded considerable quantities of copper. One 

 day, however, during a storm, a vessel anchored in the neighbourhood, dragged her 

 anchor, and was helplessly driven upon the wooden enclosure. The sea then once 

 more invaded the mine, which has not since been worked.* 



• Dufrénoy et Élie de Beaumont, " Voyage métallurgique en Angleterre." 



