http://en.wikipedia.org/wiki/Decanter seems to miss the point. ... but a carafe is a decanter in French which can have a stopper - or not.

That is Wikipedia for you, opinions and confusion! In theory some can go and correct that article but increasingly it seems to be driven by corporate PR departments selling their position.
quote: The Venetians reintroduced glass decanters during the Renaissance period
quote: Free-blown, wheel-cut carafes. First half of 11th century. Excavated at Teppe Madraseh, Neishapur, Iran.
The sample Frank shows is a water decanter for the bedside, with the upside down matching tumbler not shown.
I don't think so, it was a prestigious piece of engraving for a major exhibition, why only illustrate part of it?
But as Ivo points out the difference between carafe and decanter would appear to be artificial, at what point did the usage of the terms change in English glass? A US catalogue for 1900 uses both caraffe (sic) and water bottle to name the design of a water container that can have a tumbler. S&W at the same time also used the term caraffe (sic) to describe these. S&W also used the terms; Jug, Bottle but not decanter. I would suggest that the conventions are merely a modern desire for homogenity in terminology and that it as useful to know what terms the makers and resellers at the time of production used but that it is largely irrelevant unless the object is going to be used. Not many collectors (I do though) actually use their more precious objects, so glass ornament becomes equally applicable. So in this case the discussion of what it is seems irrelevant, only the original catalogue entry will clarify its original purpose... so who made it.. now that is interesting.