Huge coughed up some electrons that declared:
Not intending to disagree - I don;t know anything about glass flow anyway: but *what* was all that stuff about in my 5th form physics books, where they said that glass flow was detectable in stained glass in some older cathedrals, to quote from memory "glass was found to be a mm or two thicker at the base than the top after about 900 years".
Curious...
Cheers
Tim