This is a nice mid-20th century display barograph in a polished mahogany case by well known makers, Casella ltd. of London. The distinctive hexagon logo style engraved on the brass baseplate was  used by Casella from the1920s until the late1950s and I would date this example to around 1955.  Casella's trade catalogue best describes this barograph......... "The recording of barometric pressure is not only of interest to meteorologists, knowledge of its changes helps most of us to make our local short range weather forecasts. Therefore, in many public and private places there is the need for a high quality attractive looking instrument which while being useful also acts as a focal point of interest. This instrument is designed to fulfil this need and is often found in sports clubs, country clubs, town halls, hotels and large stores. It is also ideal as a presentation gift.
The case in which this movement is fitted is of highly
polished mahogany hardwood and has a lift-off cover with bevelled glass on top and on all four sides. Below the flared skirt of the base is a drawer to hold spare charts".
Weekly charts and a fresh bottle of recording ink supplied and a reprinted pamphlet describing operating instructions with guidance on interpreting chart recordings.
372mm wide x 230mm deep x 225mm high.