Glass Doesn't Settle or Why Williamsburg Made Me Look Like an Idiot

Maybe this is common knowledge with everyone, but I found out today that glass does not settle over time.

I guess my incorrect notion came from growing up in Williamsburg, VA. There you'll see all sorts of old glass that is thicker at the bottom of the pane than at the top. The common story was that it was because the glass had slowly settled over time. Apparently the correct story is that window makers spun the glass to create as flat a plate as possible. Well the centrifugal force would cause the outside edges of that plate to be thicker than the inside. Couple that with the common sense approach of installing windows with the thicker part down, and you get the result often seen in Williamsburg.

For further enlightenment check out this article.