Years ago, I took a crafts class, and the teacher called those glass grape molds. It seems to me like she said that they used to use those to mold plastic grapes or some such thing! Now, sometimes, I see them glued together at county fairs as an "instant flower arranger".
I just googled, can't find anything. They are great looking, and I love glass and wire together. Good idea on the test tube. Tuberose, if you don't mind me asking, where can I find JTV? Thanks.