A rare copy of the Declaration of Independence lost for 250 years has been discovered in London, where it is the only known example of its kind outside the U.S. Printed in Exeter, New Hampshire, just days after the Declaration was adopted on July 4, 1776, the document was intended to spread news of American independence throughout the American colonies. The early copy remained tucked away in Britain’s National Archives until a volunteer cataloging records from the American Revolutionary War came across it in May among the papers of Royal Navy captains. Only 11 copies of the so-called Exeter printing...