In A Nutshell Antiques and Interiors has dated this piece to the 1920s.
The aneroid barometer mechanism has 7 stacked vacuum capsules and utilises a gate suspension for improved sensitivity. The nib on the end of the long arm moves to record the pressure.

The clockwork mechanism is in good working order and the barograph appears to be working well. It will need setting up to the correct pressure when it arrives with you. It comes with a large number of recording charts and it has its original glass ink bottle recessed into the case which is about 1/3 full of ink. More charts and ink are readily available to buy online.

It is in excellent condition and has clearly been very well looked after. There is no damage to report and the wood has a nice aged patina. The nib is in good condition.
The best description comes from the photos so please look at them all carefully and if you have any questions at all please ask.
Nationwide postage by Royal Mail Special Delivery £25.
In A Nutshell Antiques and Interiors has dated this piece to the 1920s.
Selling good quality victorian, georgian and earlier furniture, accessories & decorative items. Ashburton, devon. LAPADA member
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In A Nutshell Antiques and Interiors is a registered member of LAPADA CINOA