Aßmann's development of aspiration psychrometers
Aßmann's aspiration psychrometer for atmospheric humidity measurements was developed between 1886 and 1889. This development was documented in two publications in German language by Aßmann in Meteorologische Zeitschrift in 1889 and 1991, which are now republished in translated form in the Classic Paper Series of Meteorologische Zeitschrift. This accompanying paper reviews briefly the history of hygrometers and psychrometers prior to Aßmann's invention and gives some details from Aßmann's vita and his development of the aspiration psychrometer. Aßmann's aspiration psychrometer is still recommended as working standard instrument today.