What does banjo mean on a wheel barometer?

It's the case outline: a circular dial above a tapering waisted body, which reads a little like the instrument. Around one in seven titles uses the word. Banjo describes shape, not date or movement. It covers Georgian mahogany cases and Victorian carved ones alike.

Which timbers turn up most often?

Mahogany dominates, at roughly a third of titles, with rosewood next and walnut, oak and satinwood behind. Flame mahogany is called out when the veneer is figured. Satinwood cases are only a handful, and they sit at the top of the range. Carved oak and walnut Victorians sit at the other end. Rosewood is the timber that most often carries mother-of-pearl inlay.

How old are these barometers usually?

Listed dates run from 1790 to 1930. Half the archive gives a clean year; the rest uses looser labels, with 19th century and 1800s the two largest groups. Regency, Georgian and Victorian are used as period tags rather than dates. Only six listings are tagged 18th century.

Is mercury or aneroid more common?

Mercury is named far more often, and it's the term attached to the Georgian and Regency examples. Aneroid appears in only a small number of titles. Those aneroid cases carry the latest style labels in the archive, including one Art Nouveau and one Art Deco, and they're generally oak or walnut. Movement internals are rarely described either way.

Why do dials carry a town name?

The dial was engraved with the retailer or maker's name and the town they worked in. It's often the only description a dealer needs for the title. The towns range widely across England: Swindon, Louth, Ludlow, Shrewsbury, Tiverton, King's Lynn, Weymouth, Colchester and more, with London on a fair share. Examples from outside England are scarce, with single pieces from Belfast, Perth and Glasgow.

Does dial size affect where a piece sits?

Larger dials sit higher as a rule. Ten and twelve inch dials appear repeatedly in the upper part of the range. The extremes work differently. A four inch and a five inch dial are both flagged as unusual rather than modest, so small doesn't automatically mean bottom of the range.