- Francium is a chemical element; it has symbol Fr and atomic number 87. It is extremely radioactive; its most stable isotope, francium-223 (originally called actinium K after the natural decay chain in which it appears), has a half-life of only 22 minutes. It is the second-most electropositive element, behind only caesium, and is the second rarest naturally occurring element (after astatine). Francium’s isotopes decay quickly into astatine, radium, and radon. The electronic structure of a francium atom is [Rn] 7s1; thus, the element is classed as an alkali metal.
- Life on the Mississippi (Wikipedia)
Life on the Mississippi is a memoir by Mark Twain of his days as a steamboat pilot on the Mississippi River before the American Civil War published in 1883. It is also a travel book, recounting his trips on the Mississippi River, from St. Louis to New Orleans and then from New Orleans to Saint Paul, many years after the war.