Re: Glass does not flow

[brian whatcott <inet@INTELLISYS.NET>]

At 14:48 8/21/99 -0600, you wrote:
> Here is someone who is learning physics from "Earth&Sky! Wow!

This comment is not described as 'ad hominem'. And yet it does
not address the science.
 The label for this kind of debating response slips my mind: can
anyone refresh me please?

> Anyone who thinks that glass doesn't flow is welcome to visit
> my 130 yr old
> house and look out the windows.

I have been made aware that a current materials science theory
 has it that old glass has not flowed despite showing very marked
thickness differences between top and bottom of panes of glass in
e.g medieval cathedrals.
     The observation is now explained on the basis of
1) the rotary production method associated with early
glass pane manufacture.
2) The widespread adoption of 'heavy side down' in  glaziery.

> In materials science common glass is clearly thought to be a fluid.
>  It has no long range crystalline structure and clearly flows.
>
> Jim Green

I fancy Jim is mistaken in attributing the tense of this theory of
 materials scientists to the present. Certainly this is what WAS
generally accepted. There has been some recent measurement of
ACTUAL glass flow rates. They do not support the former theory.

brian whatcott <inet@intellisys.net>
Altus OK