You are looking at a Tianjin Psychrometer With Turn Key. Tianjin is located in China. The psychrometer is used as a service measuring instrument. In 1818, a German inventor, Ernst Ferdinand August (1795-1870), patented the term “psychrometer”, deriving from the Greek language meaning “cold measure”. The psychrometer is a hygrometric instrument based on the principle that dry air enhances evaporation, opposed to wet air, which hinders it.

This Psychrometer comes in a brown leather carrying case. On the top of the instrument you will see a turn key. On the front of the case you will see a green plaque which has Chinese wording: Some means Ventilation, DHM2 MC, and Made in Tianjin Meteorological Ocean Instrument Factory. And on the side of one of the steel bars you will see some more writing which we think says ventilation and flat wave watch. Everything you see in the second photo is what is in the case.

This would be another great piece to add to your nautical collection!