RE: ATM between a parabola & a sphere: computation

[Anthony Stillman <atmer@flash.net>]

Donald Good wrote:
>To calculate the approximate glass removed most accurately

Yes, but that wasn't the question.  Specifically;

Guy Brandenburg wrote:
>...figure out how much glass actually gets removed when moving
>from a sphere to a parabola.


The correct way to do this is to weigh the glass before and after figuring.
I did just this one late November.  Standing on my bathroom scale, I held a
10 inch diameter spherically profiled blank in my hands and took note of
the weight.  A few days later after visiting with family and friends and
successfully figuring the blank into a paraboloid, I again stood on the
scale with the blank in my hands.  To my surprise the figuring process had
actually added several pounds to the blank.  I have no explanation for
this, though I suspect some form of deposition process must have occurred.
I hope, some November, to repeat this experiment and verify my results.

Anthony