Greg great pictures - I'm going off on a bit of a tangent here as I'm not really sure what I'm explaining or asking, but looking at your close up base pics, it appears that the vase was made with a layer of purple, then a layer of clear with bubbles over the top then a layer of clear certainly at the base. It's interesting, yet you said you can feel the bubbles on the interior of the vase. That thick casing reminds me of a cloudy vase I have by S&W which also has a very thick clear cased base.
The only thing I noticed is that compared to the pink one you linked to, your bubbles look as though they are closer together and more of them if you see what I mean? So perhaps it's not a S&W range. Sorry to not be more helpful
However if your base is flat despite the wreathing on it, then I can say it looks very similar to my cloudy vase. The difference is the clear casing on my cloudy vase is about 12mm thick. On balance I'd still be searching for an S&W link to your vase
here's a link to the base pic of my pink cloudy
http://www.glassmessages.com/index.php/topic,41369.msg228957.html#msg228957I think the pink one you linked above looks like the ones by KM in the book but is just a different shape. The way the colour graduates from darker at the top etc is very similar to the pink ones in the book as well. If it's the same range then perhaps they got the range description wrong in that linked ad when they called it 'Silver Rain'? Maybe they meant 'Silver Showers' ( or even Shower Bubbly or Cased Bubbly' - see explanation below) as the bubbly ones in the book are described as:
'This range appears in the Murray pattern book about 1938 and is called 'Sapphire Cased Bubbly'. The first pattern number, 1039A, for the pink bucket vase has a pencil annotated title of 'Silver Showers'. The two vases in pink and blue, are part of the same series. The amethyst bowl and the green vase are part of the later range, added one hundred pattern numbers later, and simply called 'Cased Bubbly'. '
So it appears they were called three different names, and from the description perhaps two different 'ranges' since they were 100 pattern numbers apart (even though they look very similar)? I'm speculating because I really don't know anything about Stevens and Williams and have never seen any pattern books. Then added to which you have the reference to S&W and Elwell range being called 'Shower Bubbly'. So maybe they produced four bubbly ranges. There doesn't appear to be a picture in the book of the Elwell Shower Bubbly to compare to.
m