gaseous ammonia is generally referred to as anhydrous ammonia to distinguish it from household ammonia, which is an ammonium hydroxide aqueous solution. gaseous hydrogen chloride is generally referred to as anhydrous to distinguish it from the more commonly used 37% w/w solution in water.
20th century. The total solar eclipse of June 8, 1918 crossed the United States from Washington State to Florida. This path is roughly similar to the August 21, 2017 total solar eclipse and was the last time totality crossed the nation from the Pacific to the Atlantic.
The August 2017 eclipse will be the first with a path of totality crossing the USA's Pacific coast and Atlantic coast since 1918. Also, its path of totality makes landfall exclusively within the United States, making it the first such eclipse since the country's independence in 1776. (The path of totality of the eclipse of June 13, 1257, was the last to make landfall exclusively on lands currently part of the USA.)