Frank, I've seen a piece at a fair that looked like the second piece you showed. I agree it is the same technique, but it does not have the same depth, complexity or sparkle.
If carbon is what vapouises to create a bubble, how come in these pieces there are huge bubbles lined with graphite? Graphite IS carbon, and if it is in a powdered form, how come it does not vapourise sooner than the presumably larger lumps that create the bigger bubbles? I think there are at least three layers of bubbles, I don't think this could be done by three casings with carbon bits of different sizes in each. I can't tell if the differing sizes are in different layers, but this would not result in huge bubbles lined with graphite powder. :?
Frank, again on the subject of bubbles (Can you tell I'm a bit obsessed with them?) do you know what creates the tiny bubble found in Nazeing? It always looks to me as if it has something to do with the particle of enamel because of the darker rim of colour around it. Again, to reassure Max, I know of somebody who thought these Nazeing bubbles were "injected" by hand.
Ivo, It was about 4 years ago I was in Germany and I was very surprised to find there seemed to be little interest in glass from the 20th century anywhere, apart from the ubiquitous WMF Ikora. The main glass interest was antique colour-cased and cut glasses. I have noticed more 20th century glass coming onto eBay from Germany recently though.
Cheers, Sue