2 EXPERIMENTAL METHODS

Cultural properties made from wood located in the ancient Egyptian collections of the Museum of Fine Arts, Boston (MFA) and the Metropolitan Museum of Art (MMA) were examined for evidence of deterioration. Objects with visual characteristics of decay were selected for sampling (table 1). Small sections of deteriorated wood were removed from the surface of each object and prepared for ultrastructural observations. Segments from each sample were cut and immediately fixed in 0.5% potassium permanganate (KMnO4) for 90 minutes, washed with several rinses of distilled water, and dehydrated through a graded acetone series. Samples were further dehydrated into 100% Quetol embedding solution for 24 to 48 hours. The solution consisted of Quetol 651, nonenylsuccinic anhydride, nadic methyl anhydride, and 2,4,6,–tri(dimethylaminoethyl) phenol in a 15:20:10:0.45 ratio. Polymerization was at 74�C for approximately 8 hours. Transverse sections of the wood (100–120 nm) were cut with a diamond knife, mounted on 300-mesh copper grids, viewed, and photographed with a Hitachi 600 transmission electron microscope (TEM). Sound wood of maple (Acer), spruce (Picea), and boxwood (Buxus) were also embedded and sectioned for comparison to the deteriorated wood.

TABLE 1 WOOD CULTURAL PROPERTIES EXAMINED FROM THE ANCIENT ENGYPTIAN COLLECTIONS AT THE MUSEUM OF FINE ARTS, BOSTON, AND THE METROPOLITAN MUSEUM OF ART

Elemental analyses were carried out on two ancient samples, where sufficient wood was available for destructive analysis, and two modern samples by multielemental inductively coupled plasma atomic emission spectroscopy (ICPAES). The samples were oven-dried, ground in a Wiley mill, and ashed at 485�C for 10–12 hours. The ash was equilibrated with 2M HCl at room temperature (24�C) and analyzed by ICPAES following procedures of Dahlquist and Knoll (1978) and elemental concentrations are reported as micrograms per gram (see table 2).