A what? A sling psychrometer is a difficult word for a very simple tool. It dates back to the 1700s and is actually still used today! If it ain’t broke, don’t fix it. A Sling Psychrometer is a simple ...

An e-mail from a Moline reader recalls an instrument using thermometers to determine humidity and wants to know what it is. It's called a sling psychrometer and consists of two thermometers which are ...