Musings about 1920s bay windows

[TheElementsSong]

I'm bored at home waiting for an engineer to change our meters and have time on my hands .

We're not planning to do anything about our windows at present (no money) but I've just realised I don't understand my own windows and was just wondering whether more knowledgeable folk could enlighten me.

So we have a 1920s house with a curved front bay window comprised of 4 panes with stone (I think) mullions in between them. Also 4 panes of lovely stained glass above these.

It appears that only one of these panes was designed to be openable as it is the only one that has a visible metal frame and handle. This is now very painted shut. It's the other 3 panes which I'm wondering about - the glass appears to be inserted directly into the stone surround, no visible frames. Is this a Thing? What keeps it in place? Or is there a secret hidden frame?

If one day we install double glazing, can this also be installed directly to the stone? (I loathe big fat UPVC frames).

Some pictures might be useful if I can upload...

First pic is the openable pane. Second pic is a "frameless" pane.

What does it look like from outside? Is it not just held in place with putty?

Sit would appear that the glazing bars inside the windo frame are put in after the glass. So, on the inside wood window frame, glass put in and nestles just inside the edge of outside stone, putty to secure and glazing bars ( wooden edges) attached on the inside.

That might be about right JT05 although I can't for the life of me determine which parts are wood. Everything has a million layers of old paint and sounds the same when I rap it with my knuckles. Outside looks essentially identical, no obvious frame.

Hmm. I can't see that they could glad without using wood, unless the windows are in a metal frame. Which now I look closely, I think they may be. The metal frame will be attached to the stone.

We have newly moved to a 1924 house and have bought The Victorian & Edwardian House Manual, by Haynes ( the car manual people) . They describe how the house was built.

Thanks for the book recommendation! I'll have a look out for it. Sounds like a useful resource for old houses.