"Dubuisson's Precision Psychrometer In Lille, 19th Century"
I'm not even sure the model in the science museum is as beautiful as this one. This exceptional 19th-century measuring instrument, called a psychrometer, consists of a dry mercury thermometer, a wet-bulb thermometer, and between the two, a circular abacus next to the graduated scale marked: "wet-bulb thermometer reading." This precision instrument comes from the C. Dubuisson company, 76 rue Colbert, in Lille. A rare wall-mounted object, in perfect condition, though it could benefit from further cleaning if desired. 
Le Magazine de PROANTIC
TRÉSORS Magazine
Rivista Artiquariato