Flowers, White, and Pforzheimer Gifts Fund Conservation of Rare Mercator Globes
Among the treasures in the Harvard College Library Map collection are two globes produced by the Flemish cartographer Gerhard Mercator (1512-1594). Renowned for his skills as an engraver, calligrapher, and maker of scientific instruments, Mercator produced distinguished maps, atlases, and nautical charts throughout his adult life and invented the Mercator projection. Among the distinguishing features of his famed terrestrial globe (1541) and celestial globe (1551) is the innovative way in which they were constructed. Twelve copper-engraved paper pieces (for the north and south poles) are contoured to cover each plaster-coated, hollow sphere as completely and accurately as possible. Mercator's creativity, command of mathematics and geography, and artistic skill yielded globes of unprecedented quality.
No other editions of the Mercator globes were produced after the first, and few survive. Until this year, Harvard's copies were in severely deteriorated condition. Tide marks (water damage), stains, pronounced surface grime, degraded varnish, fly specks, and abrasion defaced both terrestrial and celestial spheres and their accompanying painted stands. The paper gores on the celestial globe were separating in places and lifting along the seams. The paper component of both horizon rings was weak, brittle, and discolored. Losses revealed underlying wood. The wooden stands on which the globes rest were insecure because of breaks in supporting dowels. Cracks, nicks, and losses, were apparent in the legs of the stands and along the outer edges of horizon rings. Brass components were soiled and tarnished, and revealed remnants of polishing solution.
Generous gifts from J. Christopher Flowers (A.B. '79) and Mary H. White via the White Flowers; and from Carl H. Pforzheimer III (A.B. '58, M.B.A. '63) and Betty Pforzheimer have funded full conservation treatment of Harvard's two Mercator globes. The work is being carried out by T.K. McClintock Ltg. (Conservation of Fine Art and Historic Works on Paper). The Society for Preservation of New England Antiquities Conservation Center is treating the wooden stands. Extensive research usually precedes the development of a treatment plan for complex artifacts, and this was certainly true with these globes. Each was photographed and x-rayed. Varnish was analyzed, and paint samples from the wooden stands were examined in cross-section using ultra-violet microscopy. A pair of globes in Duisburg and a set of unmounted paper gores in Brussels were examined to learn more about the nature of original construction materials and finishes.
Over the course of the treatment, grime will be removed from paper surfaces using several complementary strategies. Loose sections of paper will be re-adhered, tidemarks reduced using moisture poultices, and brass components cleaned using appropriate solvents. Paper losses will be replaced with paper similar to the original in texture and weight, which has been toned to match surrounding paper, lined with Japanese paper, and adhered with wheat-starch paste. Restoring the wooden stands will involve stabilizing loose joinery, removing grime, removing darkened overvarnishes as necessary, inpainting losses, and other treatments. All materials used for cleaning and restoration have been carefully selected for long-term stability and appropriate aesthetic characteristics.
As complicated as it may sound, this conservation plan is conservative. The goal is no to make the globes look new, but rather to improve their legibility, protect them from further damage, and ensure that they remain usable for centuries to come. David Cobb, Hear of the Map Collection, remarks of the project, "Maps are a reflection of the culture that produces them. These globes reflect the art and science of the 16th century, and for the students and scholars who will use them they are a window on the past."
Nancy M. Cline, Roy E. Larsen Librarian of Harvard College, commented, "The Library has many rare and exceptional items that are of great value to scholars, but that require preservation treatment if they are to sustain any level of use. The 16th-century knowledge of the world and of the universe, revealed so elegantly in these Mercator globes, remains a reference point for many fields of study."
Continued Ms. Cline, "It is exciting to watch the restoration world progress, to see once again the detailed notations and drawings on these globes, and to know that future generations of researchers will be able to consult them. This support from Christopher Flowers, Mary White, and Carl and Betty Pforzheimer has strengthened our ability to address some of the special preservation needs that have been identified within the Library's diverse collections."