hi - the blue sounds unusual, most often these things are simply clear lead glass - the lead content accounting for much of the weight, and it's
customary to call the little blob between bowl and foot, a 'knop', rather than a knob
- and the name on the foot is described as a backstamp, rather than signed. Glass can be signed, but it's rare and occurs only on expensive or very special pieces.
If you can photograph the backstamp, that's always a plus, but you'll need more than a phone camera, and the light needs to be angled to avoid glare etc. - plus you will almost certainly need to magnify the backstamp using some form of jewellers loupe or lens which will need to be placed between the glass and the camera. It's not easy to produce good results, but practice will help you to improve
You don't say if you've tried the Replacements web site - always worth trying, although it's a mammoth encyclopedic source which can take ages to trawl through. I've had a quick look under Webb, Thomas - and it's just possible that your pattern is something they call WET 41 - discontinued apparently. I've added the link for you, so have a look yourself and tell us what you think of this suggestion, although I may well be wrong - I often am. As to type of glass, the first thing that came to mind was a sherry schooner, but other than that I'm not sure. http://www.replacements.com/webquote/BOCTHI.htm
Of course if you've already tried this site, then we may not get much further.[Mod: The above link goes to a "Bohemia Crystal" item. Webb WET41 items can be seen in the followng link: http://www.replacements.com/webquote/wetwet41.htm ]