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.
Great American Eclipse | Total solar eclipse of Aug 21, 2017. On August 21, 2017, nature's grandest spectacle -- a total eclipse of the sun -- will slide over the United States from Oregon to South Carolina. This is your guide to understand, plan for, and view this amazing sight!