A rummer is a short-stemmed glass with a large bowl standing on a heavy foot, made for wine or general table use. The word appears in 33 titles on Sellingantiques. Listings describe bucket, ovoid and pan-top bowls, and feet that include the moulded lemon squeezer type and plain square bases. Sunderland Bridge and Anglo-Irish rummers both appear.

Why do so many listings say Georgian rather than a year?

Because reign and century labels cover the ground when a precise year isn't known. "18th Century" is the largest single period figure at 98 listings, with Georgian behind it at 69. Only 168 of 484 listings carry a clean year. Where a date is given, it's often softened to c1750 or C1750-60. Decade clusters fall in the 1750s, 1860s, 1870s, 1880s, 1900s and 1910s.

How can I tell an air twist from an opaque twist?

An air twist has spirals of trapped air running up through the stem. An opaque twist has spirals of white enamel thread instead. Both are common in the category, with 33 titles naming air twists and 35 naming opaque twists. Mixed, mercury, colour and triple twists turn up as well, and opaque twists are often described as double series.

Are goblets usually sold singly or in sets?

Singles dominate, but multiples are a regular feature. Pair appears in 63 titles, and roughly one in eight listings is a pair. Sets scale further than you might expect: four, six, eight, twelve, fifteen and sixteen matching glasses all appear in the archive. Matched multiples sit well above comparable singles in the range.

What engraved subjects appear on these glasses?

Drinking subjects are the backbone, with hops and barley engraved on ale glasses. Beyond that, listings record Jacobite roses with the Fiat motto, Hanoverian liberty emblems, masonic devices, armorials and acrostic mottoes. One-off subjects include a golfer, a heron and a fish. Commemoratives run from the coronation of George IV in 1821 through to George VI, and Nelson appears as a named subject.

Which unusual forms show up in this category?

Alongside wine glasses and rummers, the archive holds ale, cordial, gin and dram glasses, sweetmeat glasses and champagne flutes. Sizes run from dwarf ale and dram glasses up to pint ale glasses and table goblets described as huge. Rarer forms appear once and not again: a cockfighting goblet, a ships glass, a deception or toastmaster glass, a Lynn goblet and a flammiform dwarf ale glass. Continental centres are thinner on the ground, with Potsdam, Nuremberg, Hessen and Liege each appearing once or twice against 20 titles simply calling a piece Bohemian.