The British have always been obsessed by the weather, and by the 19th century virtually every middle-class home boasted a new forecasting instrument.
Barometers were usually hung in the hallway so that on the way out of the house you could tap it, read the forecast and pick up an umbrella, a sun hat as whatever clothing was appropriate.
Today we tend to take weather forecasting for granted. Satellites in outer space relay weather information to earth via complex computer systems, and radio and television presenters regularly broadcast details of the coming weather hours or even days in advance. In the past, people had to rely on the simple barometer to tell them whether to expect rain or a dry spell.
The barometer was invented in Italy in 1644 by a pupil of Galileo, Evangelista Torricelli, who was conducting experiments into the measurement of atmospheric pressure. Torricelli discovered that when a glass tube holding mercury was inserted into a container of the same liquid, the height in the column varied according to the balancing atmospheric pressure in the reservoir. If water was used, the column would need to be about
10.4m/34ft high, but by using mercury, a very dense liquid, Torricelli found that the column fluctuated between the more convenient heights of only about 7lcm/28in and 79cm/3lin. The variation in atmospheric pressure was measured on a simple linear scale.
Although Torricelli died soon after making his discovery, other scientists - most notably the famous British physicists Robert Boyle and Robert Hooke - continued to develop his work, and by the 1660s barometers (or 'Torricellian tubes' as they were called) were being produced for domestic use.
TYPES OF BAROMETER
Barometers can more easily be classified by type than by date. Those based on Torricelli's original invention, with a long, narrow tube inserted into a small, usually spherical cistern, were called stick barometers. They had a long, narrow wooden case with a circular or
box shaped base protecting the reservoir.
The main alternative to these was the wheel barometer. It had a U-shaped tube with one side longer than the other. A weight was floated on the mercury in the shorter side, and a cord attached to the weight passed over a pulley wheel to a counter-balance. A pointer attached to the pulley wheel indicated the changes in pressure on a circular dial. The shape of the mechanism necessitated a change in the shape of the case, earning them the name 'banjo' barometers.
In 1844, aneroid barometers, which measured atmospheric pressure by the expansion of a small metal drum exhausted of air, were invented. Since no tube was necessary, these new barometers could be much smaller - and some were even the size of a
During the Restoration period barometers became a standard piece of furniture in prosperous home. One was generally hung on the wall next to the clock in the hall of the house, where people could easily consult it before leaving the house. Because of this position in the hall and because - until the middle of the 18th century at least - the majority were made by clockmakers such as Thomas Tompion and Daniel Quare, the case designs tended to resemble clocks.
In the 19th century barometers became increasingly popular. Large numbers were made at this time and the quality of the casing varies considerably.
Early in the century plain mahogany or mahogany inlaid with light-coloured woods were superseded by rosewood inlaid with brass. After about 1840 oak was a popular material and the better quality examples exhibited fine carving, often naturalistic in subject matter, but many were quite plain with simple straight mouldings.
After 1844 the simple, circular shape of the aneroid barometer became a familiar sight, either mounted on a decorative wall bracket or plaque, or on a plinth in the manner of a mantel clock. The majority of aneroid barometers were
made from the 1880s to the early 1900s.
Requiring no mercury, they were much cheaper to produce and therefore became available to a wider social spectrum.
For some collectors, the most appealing feature of barometers is the wording on their scales. In an attempt to cover the full range of possibilities, some allowed for conditions which were most unlikely to occur. While always written in English, the words were also sometimes present in French or Latin.
Terms commonly used included 'Fair', 'Rising Fair', 'Changeable', 'Rain', 'Stormy', 'Frost' and 'Snow'. Thermometer scales had a variety of terms ranging from 'Excessive Hot Weather' through 'Temperate Weather' to the chilling 'Excessive Cold Weather'.