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 last total solar eclipse viewed from North America was on July 7, 1972 whose path went from Northern Alaska to Nova Scotia. A second, more recent, total solar eclipse was visible on July 11, 1991 from Southern Baja California to Panama.