Vintage Nelson Knock offs bubble lamps?  

And here's the bottom.
And here's the bottom.

The ball looks like Nelson, the saucer doesn't.
Bottom of the ball isn't what would be expected, and the mounting of the bulb socket doesn't appear to be original (although it's hard to see in your photos), but it doesn't look to me like anything but Nelson.
If it doesn't appear to you that the bottom once had a metal ring that was later lost, is it possible that the lamp is a Gossamer version? Gossamer made Nelson bubbles for a time between Howard Miller and Modernica, but I haven't seen theirs up close, so I don't know whether they did the bottom that way.

Well I forgot to mention that...
Well I forgot to mention that the bubble lamp is huge and also noticed that compared to the Nelson lamps, the strings are much further apart from each other.
Also, this is probably very old. I got it from an Estate Sale. The house was very modern with glass walls etc (not an Eichler) but the house was about to fall down (circa 1951). Very deteriorated. The lamp was very dirty
I have two Nelson lamps. Smaller, and the cover, fabric or plastic what ever is called is much thinner that the one pictured here. I kind of like that since it's much harder to poke a hole through--Not that you would do that but it happens.
I though about it having a ring too but it's hard to tell because the bottom looks different than the top (where the plastic meets the metal) Also, the diameter of the top hole is different from the bottom one as opposed to the Nelson ones.
Thanks for the info.