Barometers: a collecting guide

‘It is commonly observed,’ the essayist Samuel Johnson wrote in 1758, ‘that when two Englishmen meet, their first talk is of the weather; they are in haste to tell each other, what each must already know, that it is hot or cold, bright or cloudy, windy or calm.’

Johnson was born about 30 years before the commercial production of barometers began in England, but by the time he penned this witty observation they were becoming a customary feature of middle-class households.

By the 20th century, advances in weather forecasting had made barometers largely redundant. As antiques, however, they remained highly collectable, prized for their decorative forms, complex mechanisms and historical interest.

On 25 May, Christie’s is selling 17 barometers from the collection of Sir Nicholas Goodison — a former chairman of both the London Stock Exchange and the Courtauld Institute — who wrote English Barometers 1680-1860: A History of Domestic Barometers and Their Makers, which is considered the standard text on the subject.

Ahead of the sale, Amelia Walker, Christie’s director of Private and Iconic Collections, discusses what a new collector in the field needs to know.

What exactly is a barometer and how does it work?

Essentially, barometers are instruments for measuring the weight of the air — also known as atmospheric pressure. These readings can then be used to predict shifting weather patterns.

‘Mercurial’ barometers contain a thin glass tube filled with mercury.

As air warms or cools, it rises or falls. This causes changes in the pressure of the atmosphere, which bears down on the mercury accordingly, pushing it up or down the tube.

Low pressure is associated with wind and rain, while high pressure generally pushes clouds away and brings fine weather.

The movement of mercury in a barometer was originally indicated by a scale of inches, typically ranging from 28 to 31 (the mean atmospheric pressure at sea level in England being 29.5 inches). Later, to make the readings more accessible, words were added — for example ‘fair’, ‘very dry’, ‘settled’, ‘changeable’, ‘stormy’ or ‘much rain’.

When and where were barometers invented?

Around 1643, the Italian mathematician Evangelista Torricelli — a pupil of the astronomer Galileo — set about building ‘an instrument to study the changes in air’. He realised that by suspending mercury in an inverted glass tube placed in a reservoir, he was able to create a sustained vacuum within the tube.

After several days of collecting data, he noticed that the height of the mercury in the tube changed according to the weather. This led him to suggest that the air all around us had weight, and was pushing down against the surface of the planet. This weight rose and fell in line with the temperature.

About four years later, the French scientist Blaise Pascal put Torricelli’s theory to the test. He arranged to have a barometer carried to the peak of the 5,000ft-high Puy de Dôme volcano, with the level of the mercury being recorded along the way. At the top it became clear that Torricelli was correct: the higher up you went, the less the air around you weighed.

What are the main types of barometer?

In 1695, the English clockmaker Daniel Quare patented the first ‘cistern’ barometer, which was sealed to prevent the spillage of mercury. This important step made barometers safer, more accurate and more easily portable.

Around the same time, ‘wheel’ barometers were also invented, with a large dial linked to the mercury tube by a pulley. As the liquid moves, an arrow points to labels indicating various weather conditions, allowing for quick and clear interpretations.

The 18th century saw the development of ‘angle’ barometers. These have a bend in the tube before the lowest point to which the mercury can recede. This means the mercury moves a greater distance along the slope as it rises and falls, giving more detailed readings.

In 1844, the French engineer Lucien Vidie produced an ‘aneroid’ barometer that used springs to support an evacuated capsule, which measured air pressure. Because his invention didn’t require any liquid, it was easier to carry, making it particularly useful to sailors and mountaineers.

As scientific instruments, barometers often came with ancillary features, including thermometers for reading the temperature, and hygrometers for measuring humidity. Occasionally, they were also fitted to longcase clocks.

Who were some of the key barometer manufacturers?

Initially barometers were the preserve of scientists. During the 17th and 18th centuries, however, production for the consumer market began and they became highly decorative.

Early examples were mounted in walnut, then in more exotic timbers such as rosewood and mahogany, and they were embellished like clocks and other items of furniture.

At the peak of their popularity, there were some 2,000 barometer makers and retailers in England alone. Other makers could be found in France, Germany, Holland, Ireland, Scotland, Belgium, Portugal and America.

George Adams was one of the most eminent instrument-makers of the 18th century, known especially for his globes and microscopes. He was appointed Mathematical Instrument Maker to King George III.

A catalogue of his products lists ‘curious barometers, diagonal, wheel, standard or portable, with or without thermometers’, with prices ranging from £2 to £16.

His barometers are celebrated both for their high-quality mechanisms and for cases adorned with scroll pediments and brass finials.

Barometers by his sons, George Adams the younger and Dudley Adams, who both succeeded him in the business and the royal appointment, are also of particularly high quality.

Charles Orme was a celebrated 18th-century maker of angle barometers. Some of his instruments contain two or occasionally three tubes, extending the usual distance that the mercury can rise or fall from three inches to 60 inches, giving even greater accuracy. He also pioneered the practice of distilling the mercury to remove any impurities.

Originally a blacksmith, John Russell rose to become one of the best-known clockmakers of his day, and was eventually appointed Watchmaker to the Prince of Wales, later King George IV.

Russell is renowned for his wheel barometers, which, owing to his clockmaking skills, have finely engraved plates and intricate mechanisms. Today, his barometers can be found in Buckingham Palace and the National Galleries of Scotland.

Other key names to look out for include Benjamin Martin, Watkins and Smith, Thomas Jones, John Whitehurst, Balthasar Knie, Negretti & Zambra, and Justin Vulliamy, who was known on occasion to work in collaboration with the cabinetmaker Thomas Chippendale.

What do collectors look for?

Besides rarity, and the importance of the maker and retailer, collectors prize quality, condition and patina.

Barometers made by expert craftsmen will always command a premium. Details such as beautiful lacquer-work or skilfully carved ornaments are highly prized.

Owing to their fragility, many barometer parts often need replacing, especially the glass tubes. Where this is the case, the key consideration is that the work has been done sympathetically and the parts are as close to the originals as possible.

Patina refers to how the colour of the wood has changed with age. Collectors like to see a natural accumulation of oils on the surface, making it appear darker. Anything that has been over-cleaned, or neglected, should be viewed with caution. Gentle care is crucial.

The same rule applies to any metal elements, including dials and hands.

Interesting provenance is also appealing. For example, Sir Nicholas Goodison was known to buy only the best barometers, working with reputable auction houses and dealers. For a piece to have been included in his collection is an indication of quality.

What is the market like for barometers?

The market for quality barometers is small, but competitive.

Many of the most important examples belong to museums, including the British Museum, the Science Museum and the Victoria and Albert Museum in London, the Metropolitan Museum of Art in New York and the Getty in Los Angeles.

As a result, barometers of the highest calibre seldom appear on the market — meaning that the sale of the Sir Nicholas Goodison collection at Christie’s presents a rare opportunity to acquire some exceptional examples.