Bing found the following results
Hygrometer - Wikipedia
Hygrometer - Simple English Wikipedia, the free encyclopedia
How to Test a Hygrometer: 6 Steps (with Pictures) - wikiHow
Humidity - Wikipedia
Hygrometer - Wikiwand
Hygrometer | Humidity, Moisture, Measurement | Britannica
Hygrometer | Encyclopedia.com
How hygrometers work | Measuring humidity - Explain that Stuff
Thermo-hygrograph - Wikipedia
What is a Hygrometer? | Types of Hygrometers - Measure …