[no subject]

["Kenneth J. Morgan" <kmorgan@UP.NET>]

Yes, the math teachers in my high school had these. That was 1960-1965.
Never have seen one since.

Ken

At 10:29 AM 4/6/99 -0500, you wrote:
> Phys-l,
>
> All this talk about whiteboards has triggered a question I have about
> blackboards.  In high school, my teacher had a thin square pad, about 1
> meter on a side, with many tiny holes in it.  When he placed the pad
> against the blackboard and rubbed a chalk-filled eraser over the surface,
> the chalk bled through the
> holes and formed a nice grid (made up of little dots) on the blackboard.
>
> I have asked numerous vendors and manufacturers for this product and not
> been able to find it.
> Am I remembering incorrectly?  Have you seen this kind of thing before?
>
> Mark
>
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>
> Mark J. Lattery                                           Phone:
(920)424-7105
> Assistant Professor of Physics                   Dept:  (920)424-4433
> Department of Physics and Astronomy     Fax:   (920)424-0894
> University of Wisconsin Oshkosh              Email:   lattery@uwosh.edu
> 800 Algoma Boulevard
> Oshkosh, Wisconsin 54901-8644
>
> "Physical concepts are the free creations of the human mind and
> are not, however it may seem, uniquely determined by the external world."
>
> --Einstein in "The Evolution of Physics" (1938)