In A Nutshell Antiques and Interiors has dated this piece to the 1930s.
The centre is marked with the maker's details "Surveying Aneroid Compensated. E.R.Watts & Son, London. 2972". There is a magnifying arm which can be used around the edge of the barometer to read the dial.

It is in good condition for its age. The glass is clean and has no major surface scratches. The face is clean and bright with no damages. The case has a nice aged patina with some light scratches and marks but nothing detrimental and it displays well. It seems to be in working order. I've done 'the bag test' and the pointer certainly moves as it should do but I cannot guarantee its accuracy as I haven't referenced the readings.
The best description comes from the photos so please look at them all carefully and if you have any questions just ask.
Tracked UK delivery £10.
In A Nutshell Antiques and Interiors has dated this piece to the 1930s.
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