A substance is anhydrous if it contains no water, for example, salts lacking their water of crystallisation. The way of achieving the anhydrous form differs from one substance to another.
A partial solar eclipse at its peak at 3:37 p.m. in Mesa on Oct. 23, 2014. The eclipse was visible over most of North America and covered 44 percent of the Arizona sun. Michael Chow/The Republic.
21 August 2017: Solar eclipse seen in all of North America including total eclipse crossing the heart of teh USA. 11 August 2018: Partial eclipse in northeastern parts of North America.