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.
This eclipse will be the first total solar eclipse to be visible in Mexico since the solar eclipse of July 11, 1991. The path of this eclipse crosses the path of the prior total solar eclipse of August 21, 2017, with the intersection of the two paths being in southern Illinois in Makanda just south of Carbondale.