WELL, 25 people have looked at my little cup, with no comments. today, I got the cup in the mail, and took some fresh photos and measurements. here is the link:
(left: UV, center: indoor room with room light only, right: outdoors in bright sunlight)
http://www.vaselineglass.org/cutcuptrio.jpgthe height is 3 1/2" exactly (not the original 3 1/4" the seller quoted). the top diameter is 2 7/8". The foot is 2 3/16" square. The glass has a lot of swirls, micro bubbles, impurities that show up under a 5X loupe. It also sings! when lightly flicked, it will sing audibly for a full five seconds! I knew it was cut, but it has a great bell tone!
Coincedentially, I sat it next to the swan salt I got at Harrisburg, PA (Nat'l East Coast Antique show) and the first thing that caught my eye was the similarities of the base.
http://www.vaselineglass.org/squarebasetwins.jpgThe bases are so close in size (minus the little chip, of course) that they are within 1/16th of an inch to being a match, and 1/32th of an inch to being an exact match for thickness! I think this may be a bit more than a coincedence and I have to at least entertain the possibility that it could possibly be the same factory that made both of these. the color is off just a little as far as comparing the two, but I also know that color quality control was not an exact science back in the 1840-50 era (or even 1880s!), so that does not automatically make it a different maker. The simplistic cutting, the impurities and bubbles, the overall style, etc, just makes me think that this is most likely English, about 1840-50 for a time frame.
as always, comments are appreciated.