We’ve all heard of or even visited the Smithsonian. But how did the institution that houses our nation’s treasures come to be? This hour, we’ll learn how the 18th Century bequest of an Englishman who never visited America led to the founding of the institution in 1846. Our guest is Heather Ewing, author of “The Lost World of James Smithson: Science, Revolution and the Birth of the Smithsonian” (Bloomsbury USA, 2007).