The Spring Barograph

No, it's not about the time of year!

Manufacture of the typical barograph has been in production for almost 150 years and over the decades there have been numerous variations to the original design. Leaving aside the outer case (which could form the discussion for a later blog) these tweaks to the actual working mechanism have generally been made for reasons of style, accuracy and economy etc. The variations seemed to have been in fashion for short periods and then returned in favour of the traditional and more recognisable style, presumably to satisfy market demands.  In fact, the traditional style was still the most popular until all production of 'domestic' barographs in the UK ceased about 10 years ago.

One particular design variation which I believe was underrated is the ‘Spring’ Barograph.

A respected professor and colleague agrees and has several of these sprung barographs explains:

‘In simple terms, the diaphragm stack is held apart by either a simple heavy weight or firmly anchored with a sturdy spring allowing the minute flexing of the stack to be transmitted on to the recording chart - even with the smallest of atmospheric pressure changes. Richard Freres of Paris were so confident in their weighted barograph that a large version was used as a local seismograph when contractors were building the Paris Metro’.

Interestingly, the Canadian Meteorological Service developed a sprung barograph in the 1950s and was used in their version of the British Met Office Open Scale Barograph.

 The two standard size barographs which gave me the idea for this blog are signed by different and very renowned makers, Thomas Armstrong of Liverpool and J.H.Steward of London, circa 1912 . Both of them carry the "Patent Applied For" label. The Steward example will shortly appear on my website in an concerted effort to reduce my collection.