A.Oldham (P.H.I.M.H) & Son Clock Makers  

 

Precision Horological Instrument Makers & Horologists

 


Established 1949

 

 

 

0800 211 8925

 

barograph repairs

 

We will only offer for sale the finest instruments available in full working order and exceptional condition.

Our barometers for sale are listed by maker in the highlighted sub pages indexed on the left.

Should you wish to ask any questions we will be only too happy to hear from you.  

   

The barometer is a scientific device used to measure changes in atmospheric pressure.

In use since the 16th century, barometers typically are applied to meteorological studies.

The earliest barometers were simple devices, made of glass and filled with water.

Later iterations used mercury or enclosed bellows to measure air pressure.  

 

Water Barometers

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Among the first barometers invented, water barometers, sometimes called storm glasses or Goethe barometers, became widely used in the 17th century.

Consisting of a sealed glass container with an upturned spout on one side, this barometer contains water that fills the bottom half including the spout.

As air pressure changes, the level of the water in the spout rises or falls.

While typically not very accurate, water barometers were still used by many to determine when air pressure dropped indicating an approaching storm.

For the casual weather observer, water barometers are still available today.

 

Mercury Barometers

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To increase the accuracy of a barometers, scientists in the 18th century developed several different types of barometers using the liquid metal mercury, rather than water.

The heavy weight of mercury allowed for minute measurements in barometric pressure change.

These barometers typically consist of a long sealed glass tube filled with mercury that sits within a well of mercury at the bottom.

The Fortin barometer is a classic example of a mercury barometer.

In a Fortin barometer, the glass tube with mercury and the well are both encased in a metal housing.

The mercury is visible through windows in the housing, which holds a scale by which the level of mercury is read.

Mercury barometers are still used today, particularly for scientific purposes.

 

Aneroid Barometers

anerioid barometer repair

The concept for aneroid barometers was around for over a century before its invention in 1843 by French scientist Lucien Vidie.

This was the first portable barometer, as mercury barometers were sensitive and easily damaged when moved.

Aneroid barometers use a small sealed bellows that maintains a constant pressure.

When the atmospheric pressure changes, the bellows either contract or expand under that pressure.

This contraction or expansion moves an actuator needle indicator that points to the meter on the dial of the barometer.

Some aneroid barometers are fitted with a pen that marks a turning drum covered with graph paper.

Called a barograph, this device track changes in barometric pressure over time.

    

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