Encyclopedia of Exploration 1850 to 1940: Continental Exploration, by Raymond John Howgego; Hordern House Rare Books, 2008, $295. The literary undertaking that the distinguished critic Alberto Manguel described as “The definitive reference book for anyone interested in the history of travel”, has now been brought to a triumphant conclusion in its fourth volume devoted to continental exploration from 1850 to 1940. As its seemingly tireless author, Raymond John Howgego, notes in his helpful and succinct introduction, the period covered in this volume differs greatly from those covered in its three predecessors. Well before the end of the nineteenth century it…