Today I posted a picture of a R Fuess black bulb thermometer that was recently added to my instrument collection. Black Bulb thermometers were used since the 1800s in an attempt to quantify solar radiation, though this was not very successful. I'm not sure of its age, but a similar device is shown in the 1940 R Fuess catalog available on this website.

Black bulb thermometers are still used today to calculate WBGT (Wet Bulb Global Temperature), a measure of stress on the human body due to weather. The device is located in the pyranometer section of the website. Go to R Fuess Black Bulb Thermometer web page.