> I've lived in houses with original window glass from pre-1900 I live in a house from around that time. I just spent some time replacing the front window with

> I've lived in houses with original window glass from pre-1900 I live in a house from around that time. I just spent some time replacing the front window with double glazing. The original glass was 2mm thick. It was bending precariously as we removed it from the frame. How in the world that glass survived as long as it did will forever be a mystery to me.