Today is the birthday of Johan Gadolin, born in 1760, he discovered the first rare earth element yttrium. Although yttrium is a transition metal, it is always found in minerals with the lanthanides, so it is often considered a rare earth element. He found it as an oxide in ytterbite, a mineral discovered by Carl Arrhenius, Frederick Wohler was the first to isolate the element.
6/5/1819 John Adams, astronomer, he used mathematics to predict the existence and position of Neptune. He died in 1892 at age 72.