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.
The 2017 Total Solar Eclipse in Tennessee. On 2017 August 21, a total eclipse of the Sun is visible from within a narrow corridor that traverses the United States of America.