In retirement, Jefferson pursued science and natural history through research, experimentation, and invention. He continued in his post as the elected president of the American Philosophical Society until 1815. He tackled Plato's Republic in the original Greek as well as Greek versions of the Bible.
A "New Frontier" was used by John F. Kennedy in his presidential acceptance speech in the 1960s. Space is described in the speech as the "New Frontier".
