(331 Bgde was part of the East Lanc's Bolton Royal Field Artillery Regiment). It is set into a weighted & hallmarked solid silver 4.5H stand made by Sydney & Co of Birmingham, which is in good condition with the odd imperfection commensurate with its age and the hallmarks although just readable, are polished worn.
At the time of the photo it was indeed raining and so the compensated barometer is reading true and has an adjuster to the back. Great piece of WW1 memorabilia with the added bonus of a much sought after scientific instrument by Negretti & Zambra!