This is a mahogany cased barograph signed James Brown, 76, St. Vincent St, Glasgow. Curiously, it is titled Improved Barograph. I can only assume this refers to the small weight hanging on the horizontal link between the diaphragm stack and the pen arm link to take up slack in the movement.
The instrument has heavy bevelled glass to the lift-off lid and an impressive cut glass ink bottle and stopper which looks to be original.
A selection of weekly charts will be included together with a fresh bottle of recording ink, red or blue, and a re-printed copy of a pamphlet by Negretti and Zambra (who later took over Short and Mason) describing operating instructions and the interpretation of various chart recordings. 
355mm wide x 206mm deep x 191mm high