Glass Message Board

The base is moulded, so it probably always had fittings of some kind on top. I don't see any reason why the Messenger parts would be an addition, although the bulb-holder could be.

That said, the thread on the top of the Messenger part, where the bulb-holder attaches, is 1/2" / 26tpi, which was the British standard for electric light fittings (and motorcycles), and not too much else as far as I know.

It's a bit baffling.

Mikasa used this part frosted/part clear effect.  I had a leaf shaped huge bowl that was similar in that the frosted part was thick and rounded if you see what I mean?  Very heavy.
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Don’t know who this is from, maybe Durand? It is about 160mm diameter.

The frosting is by sand blasting (or other abrasive blasting). Looks like a stencil was used as you can see in places where the edge of the frosting has spread under the stencil where the stencil wasn’t in contact with the surface, leaving a less sharp fuzzy edge. There are none of the scratches you see when the surface has been abraded by scrubbing (rather than blasting). The tiny pits from the blasting look a similar size to an acid frosted finish but more angular rather than spherical with acid.

I've tried it against some plain black sheet, but it's still reflective. I've left the flash off to get the cuts showing, and sketched the pattern, which just repeats the three bars and cross hatch round the sides.

The bubbles are a little bit Biot-ish, but I don't know if they were going that long ago and I don't know if they ever made lampshades.