The Age of Discovery

The ideal gift for a special occasion

Dalvey barometers are precision-engineered, beautiful, reliable and portable. A German aneroid barometer is housed in mirror-polished stainless steel casing; each stunning face combines striking dials with raised increments and meteorological details. Perfectly suited to personalisation, the barometer can be engraved with initials, dates, a name, or a memorable phrase - making it an ideal gift for a special occasion, and the perfect design-led feature to ornament a desk, mantelpiece, bookshelf or counter-top.

A point of difference...

The original Dalvey Barometer was developed shortly after the launch of our iconic Voyager Clock – and shares the same clam-shell-like case design and striking presence when open and displayed. Our latest editions feature luxury-watch-standard dials in a range of differentiated characters: from deep, rich blue, through exuberant turquoise, to elegant grey with rose gold accents – perfect for adding a point of colour and elegant design to a kitchen, study, reception, or hall.

Horror vacui

The barometer is widely credited as the invention of Evangelista Torricelli, who built the first working version of a mercury barometer in 1643. In fact, Descartes is credited with having conceived of the barometer some years previously but is not thought to have built such an instrument.

There would be no barometer without the recognition that a vacuum is possible in nature – contra Aristotle’s assertion of the horror vacui, or nature’s abhorrence. In the Seventeenth Century it was assumed – even by Galileo – that air had no weight. The proof that this was not in fact the case emerged from a very practical exigency: Tuscan miners were struggling to pump water over a vertical distance of 12m, using suction pumps, but found that they could only raise the water by 10.3m…

Torricelli’s experimental paradigm involved placing a long glass tube containing a column of water into a shallow pool (Fig. i). When the stopper at the bottom of the tube was removed, Torricelli found that the column of water descended (creating a sealed vacuum at the other end of the tube), but only so far as to allow its height to equal the threshold of 10.3m over which the miners had struggled to pump their water.

Torricelli realised that it was the downward pressure of many kilometres of air above the water in the open pool that was preventing the column of water in the tube from fully descending into the pool, and recognised that this first barometer was actually a kind of balance: equalising the respective pressures of the air above the open pool, and the column of water in the tube. This realisation prompted Torricelli to build a much smaller, more practical version - using mercury. Since mercury is around 13 times denser than water, it’s effectively able to fall farther than water would, and so the height of the column of mercury fell to about 76cm – much less than the 10.3m height of the water. This greater density meant that mercury barometers could provide useful readings even when much smaller than those using water.

The barometric altimeter

The French mathematician, Blaise Pascal, realised that if air had weight, then presumably air pressure would be lower at higher altitudes – the less air there is above your head, the less of it there is weighing down upon you. In 1648 he asked his brother-in-law to carry a mercury barometer up a mountain, recording the height of the mercury as he rose. As predicted, the air pressure was lower the further up he went. As such, when properly calibrated a barometer may also function as an altimeter.

Twelve years later, in 1660, the German scientist, Otto von Guericke, observed from a barometer that air pressure had been falling. He correctly predicted a storm would come, and hence initiated the meteorological use of barometers.

The aneroid barometer

The first barometer to function without liquid was invented in 1844 by the French scientist, Lucien Vidi. The “aneroid” barometer relies on an “aneroid cell”: a small metal chamber containing a partial vacuum. The cell is prevented from collapsing in upon itself by a strong spring; this allows changes in air pressure to manifest as slight changes in the volume of the cell (the less pressure, the more the spring is able expand the walls of the cell; the more pressure, the more the atmospheric air is able to push in upon the walls of the cell, contracting its volume).

The slight changes are amplified by a system of levers and springs, which alter the tension on the ‘fusee chain’. This tension is translated into radial movement via the ‘hairspring’ and pointer so as to be easily read upon the face.

Dalvey barometers contain a reliable German-made aneroid cell (or “bellows”) and mechanism: no liquid is involved.

The Age of Discovery

Notable among the innovators who developed barometric technology was the English naval officer, scientist, one-time Governor of New Zealand, and Member of the Royal Society, Robert FitzRoy.

In addition to captaining the HMS Beagle, during which he enjoyed the company of Charles Darwin, FitzRoy developed a number of new barometer styles, and is thought to have coined the phrase, “weather forecast”. He was appointed as chief of a new government department, which would evolve into today’s Meteorological Office. Since 2002, when one of the regions of sea surrounding the British Isles was renamed from “Finisterre” to “Fitzroy”, he has effectively been commemorated twice daily by the BBC, during its famous shipping forecasts.

Using a barometer...

It’s important to remember that the meteorological value of a barometer comes from its measurement of changes in air pressure, as opposed to the absolute measurement values (which have greater altimetric value). The ‘reference pointer’ should be pre-set to match the initial pressure reading, after which observations of rising pressure denote improving weather, and falling, the contrary.

Gifting: perfectly calibrated

Each Dalvey Barometer comes in beautiful presentation packaging, and can be personalised with engraved initials, a name, a date, or a memorable phrase. This, together with its connotations of preparedness irrespective of conditions, makes the Barometer an ideal gift to mark a moment of significance or a special juncture in life, such as a wedding, graduation, retirement, or an especially important birthday.

Over the years we’ve had the privilege and pleasure of engraving hundreds of messages on barometers; some of our favourites have been quotes from some of the explorers and adventurers who would have so vitally depended upon their barometric and navigational instruments:

Optimism is true moral courage
Shackleton

You learn to know a pilot in a storm
Seneca

It is the work that matters, not the applause that follows
Scott

Every cloud engenders not a storm
Shakespeare