In message , Dave W
writes
"News" wrote in message
...

Tangent alert! Our windows are all still original Victorian sash, and
many panes (with flaws) are probably original, too. One bedroom window,
at the front, is odd. Traditional sash, with four panes of glass, yet one
of the four always looks as though it is not there, from outside. It just
looks dark, and you would think the whole pane was missing. Looking out,
from the bedroom, it looks exactly like the other three. No idea why.

Interesting. Perhaps it has a non-reflective coating on it, sometimes used
on swish buildings and picture frames.

Possible, I suppose, but why? Why would anyone use anything but plain,
ordinary domestic glass? I don't know. First time I noticed it from
outside, I ran upstairs, thinking the pane had been broken, convinced I
would find a golf ball or similar in the bedroom.

--
Graeme