Five years ago the Osher Map Library and Smith Center for Cartographic Education opened with an exhibition called Treasures of the Collection. The objects then on display were drawn from the library's two founding collections, formed by the late Lawrence M. C. and Eleanor H. Smith and by Dr. Harold L. and Peggy L. Osher. Outstanding specimens from these collections were designated as "treasures" by virtue of their historical importance, their rarity, or their beauty and cartographic craftsmanship. Additional items were included to demonstrate the breadth and scope of the collection. The overall intent was to emphasize the rich cultural content and multi-dimensional nature of maps and their powerful capacity to enlighten and to entertain.

The current exhibition, Worldly Treasures, differs from the inaugural exhibition in several respects. By virtue of significant additions to the collection, largely through gifts from a variety of donors, the items on display are drawn from multiple sources. Many are recent acquisitions. Furthermore, the criteria for designation as a "treasure" has been broadened considerably to include what might be termed "undiscovered treasures." Examples include nineteenth-century school geographies and atlases, student manuscripts, bird's-eye views of Maine cities and towns, and municipal insurance maps. These items, while not as rare or beautiful as, for example, renaissance maps of discovery, are nonetheless historically important in their own right. They constitute a vital resource for the study and understanding of American history, educational concepts and methodology, and municipal development. Because their value is often unrecognized, many of these objects have been discarded, and they may consequently be classed as an "endangered species." It is hoped that this exhibition will increase awareness of the need to preserve them.

The Osher Map Library's ability to produce exhibitions of this sort and expand its teaching resources is critically dependent upon acquisitions that broaden the scope of its holdings. In large measure, this diversification has been and will continue to be contingent on the preservation of these valuable artifacts and their donation to the map library.
 

This map, reproduced as the exhibition poster, is from a sixteenth-century edition of the classic geographical text by Claudius Ptolemy of Alexandria. Written about AD 150, Ptolemy's Geographia laid out the basic principles of scientific geography and mapmaking. When the book was rediscovered by scholars in the Latin world at the start of the Renaissance, it was adopted as the ultimate authority on making maps of the world and its regions. The features of Ptolemy's maps--such as their orientation with north at the top and their use of latitude and longitude coordinates--became the standard hallmarks of modern Western cartography. For this reason, Ptolemy has been called the "Father of Geography."

Ptolemy's few "errors" resulted from limited or faulty geographical information, especially for distant places. His most celebrated error, placing the earth at the center of the universe, had little practical consequence. However, Ptolemy's underestimation of the size of the earth and the width of the Atlantic Ocean encouraged Christopher Columbus in his belief that a westward crossing from Spain to Cathay was feasible. Ptolemy's hypothesis that southern Africa and eastern Asia were joined by a large southern land mass, terra incognita, had a mixed reception in Renaissance Europe: the land bridge is seen on some editions of his world map (e.g., 7) but is lacking here.