What is the difference between a stick and a wheel barometer?

A stick barometer is the slim upright form: a mercury tube behind a narrow case, with the reading taken from a scale at the top. A wheel barometer has a round dial and a pointer driven by a float sitting on the mercury. Wheel barometers commonly carry a thermometer, and often a hygrometer and spirit level, in the same case. Stick barometers are usually just the tube and its register plate.

Why is banjo used for some of these?

Banjo describes the case shape of most wheel barometers: a round dial over a tapering body. In these titles the two words point at the same object, and some dealers use both in one description. 'Wheel' appears in thirty-two titles and 'banjo' in twenty-three.

How old are most examples on the market?

The dated field runs from 1700 to 1930, and seventy-six of one hundred and sixty-seven listings carry a clean year. Where a decade is given, the 1850s through the 1880s account for the bulk. Only six listings are filed as 18th Century, against thirty-four filed simply as 19th Century. The paperwork is much vaguer at the early end than the sampled dates suggest.

Are these mostly English?

Almost entirely. The archive is dominated by English domestic pieces in mahogany or rosewood, signed with a surname and a town. Non-British origins are the rarest thing in the category: a Milan-signed ebonised stick, a Paris-signed piece, one Dublin maker and one described as American carved walnut.

What does a storm barometer look like?

It is a late-Victorian pattern, usually in carved oak, with printed forecasting instructions set into the case alongside the tube. These form a small distinct group. 'Oak' appears in eleven titles, and four sampled titles name the storm pattern.

How many come up for sale?

Fifty-two dealers have listed in this category on Sellingantiques, at a rate of about fifteen pieces a year. That makes supply broad but thin. Most dealers who carry one carry only one.