"Very Large Manometer"
Maximum diameter: 73 cm! By Bourdon, inventor of the system of measurement of the pressure consiting in a flattened tube which was evacuated and which deforms under an external pressure (barometer) or for manométres, deforming under an internal pressure by communication with a steam engine boiler for example. Very decorative and spectacular object, ideal in an industrial decoration in a loft. Period late nineteenth. 
Le Magazine
Rivista Artiquariato
TRÉSORS magazine