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Small detail: The Lady Isabella (shown on the 2nd series 1:50K map, Sheet 95 as the "Laxey Wheel", which is how she/it was generally known, at least 50 years ago) is at Laxey, not Foxdale. The actual shaft is (was) several hundred yards further up the valley towards Agneash, the wheel driving the pumps through a very long iron "rod" traveling back and forth on rollers - almost as amazing a piece of engineering as the wheel itself. It should be fairly easy to calculate the weight of water on the buckets of a wheel, and the moment about the axis, and hence the weight of water that could be lifted, assuming the rising main could stand the pressure. Theoretically, you'd need a string of about 45 suction pumps to get the Laxey Mines' water to the surface! (one for approx. each 10 m or 5 fm of depth). If there were one giant lift the pressure at the bottom would be about 640 p.s.i. (45 kg/cm2). I have no idea how that compares with the strength of iron barrel staves or early cast-iron pipes, but I wouldn't want to be around if one burst! (Where I live we have mains water pressure of up to 80 p.s.i., and that causes a lot of problems with older pipes, especially at bends and joints). John Berry Automatic digest processor <[log in to unmask]> wrote: There are 4 messages totalling 216 lines in this issue. Topics of the day: 1. Pumping (3) 2. CEAG lamps ---------------------------------------------------------------------- Date: Fri, 4 Apr 2003 23:53:46 +0100 From: Rick Stewart Subject: Re: Pumping The "piece of string" in question is Devon Great Consols. In a moment of idle speculation I was wondering how close to the limit the two 40' x 12' wheels which were pumping Wheal Anna Maria and Wheal Josiah (max depth circa 150 fathoms) were. I was also wondering what would have happened if tin had been discovered below the copper and the mine went deep, say 300 fathoms? Would the mine have persevered with water power for pumping or would they have turned to steam? Rick John Berry Associates Geology & Remote Sensing 5000 Beverly Hills Drive AUSTIN, TX 78731, U.S.A. +1-512-452-8068 (Voice) +1-512-413-9270 (cell) [log in to unmask]