A.P. wrote:
"Phil Kangas" wrote in message
...

Here's an interesting site concerning the experiments
done with plumb lines in the Tamarack Mine near
Calumet Michigan in 1901. This has been recognized
by the Guiness Book of world records just lately.
Metal content : this is a copper mine...............
Phil Kangas

http://www.lhup.edu/~dsimanek/hollow/tamarack.htm




I find it strange that the Chef Ingeneer (and owners) allowed a 4000' long
pipeline to be supendend only at the top ! ( it should snap !? )
They would make supension at every 30' ! The pipes are made to cary
something, maby liquid , that will make the pipe X times heavier !
Not PIPE lines, PLUMB lines. In this case, I suspect they were steel
music wire, not string.

And, the cause of the anomaly is obvious! The plumb lines were being
attracted to the walls of the shaft. There was nothing but air between
them, but there were the walls of the shaft on the exterior. They hung
the lines quite far apart (12 to 17 Feet), when they could have hung
them just a few inches apart. I suspect if they plotted outward
deflection against spacing, they'd find a NON-linear relationship,
while the gravitational effect SHOULD have been linear (and the other
direction, of course.)

Jon