The history of the rise and fall of Huel Wherry,[54] a tin mine which was opened, more than a century ago, in the midst of the sea, near the town of Penzance, is too interesting to be passed over in silence. In this place a gravelly bottom was left bare at low water. Here a multitude of small veins of tin ore crossed each other in every direction through elvan rocks, and were worked whenever the sea, the tide, and the season would permit, until the depth became unmanageable. About the year 1778 Thomas Curtis, a poor miner, was bold enough to renew the attempt. The distance of the shoal from the neighbouring beach at high water is about 120 fathoms, and this distance, in consequence of the shallowness of the beach, is not materially lessened at low water. It is calculated that the surface of the rock is covered about ten months in the year, and that the depth of the water upon it at spring tide is nineteen feet. A very great surf is caused, even in the summer, by the prevailing winds, while in winter the sea bursts over the rock in such a manner as to render useless all attempts to carry on mining operations. Yet all these difficulties had to be overcome by a poor uneducated man. As the work could be prosecuted only during the short time the rock appeared above water—a time still further abridged by the necessity of previously emptying the excavation already made—three summers were spent in sinking the pump-shaft, which was a work of mere bodily labour. A frame of boards, made watertight by pitch and oakum, and carried up to a sufficient height above the spring tide, was then applied to the mouth of the shaft. To support this boarded turret—which was twenty feet high above the rock, and two feet one inch square— against the violence of the surge, eight stout bars were applied, in an inclined direction, to its sides, four of them below, and four, of an extraordinary length and thickness, above. A platform of boards was then lashed round the top of the turret, supported by four poles, which were firmly connected with these rods. Lastly, upon this platform was fixed a windlass for four men. Footnote 54: ‘Cornwall, its Mines and Miners.’