This is a combined barograph &  thermograph which has all the hallmarks of a Short & Mason London, instrument, circa 1950. The light Mahogany (or possibly Walnut) hardwood case has a lift off lid and deep bevelled glass all round. There is an 18mm diameter circular hole in the centre of the small panel at the right hand end to allow the air circulation for more accurate temperature readings. At the base of the case is a chart drawer. The diaphragm set within the barograph movement is the improved  version of separate bellows which began to be used from the mid-1930s until the concertina type was introduced in the 1960s. The thermograph sensor is of the traditional bi-metallic coil design.
Both original pen arms are gravity hinged of the post war gate suspension type and are engraved 'Barograph' and 'Thermograph'. There are two separate ink bottles - red for barometric pressure and green for temperature. The whole movement has been designed so that both traces record on the chart and the pens freely pass each other.
A quantity of the correct dual recording charts are included together with two bottles of coloured ink. A copy of a reprinted pamphlet describing operating instructions and interpretation of barometer trends is also included. 
367mm wide x 230mm high x 232mm deep.