Silk fibers elemental composition

Data obtained in the EDS analyses are listed in Table I. The fiber standards (primarily organic ) gave broad EDS spectra. No heavy elemental composition was indicated in silk, and only a small quantity of calcium could be detected in linen. No elemental maps could be obtained for silk or linen. The EDS spectra of wool reflected its sulfur content. In some of the samples, the somewhat higher concentration of sulfur in one-half of the cross section, which is expected of this naturally bicomponent fiber, was apparent (7). In other samples, the differentiation was not clear. 

The extent of extraneous deposits on the Marine specimens varies widely. Some areas are almost completely free of deposits, others have moderate amounts of deposits, and some areas are so heavily covered diat die fiber surface itself is not visible. Of die Marine Silks, 29049 and 33707 have die most deposits, and 29054 has fewer deposits. In comparison with the Historic Silks however, all Marine Silks have more deposits. These deposits appear very different from those observed on the Historic Silks. The first is a continuous pastelike deposit with small beaded structures less than 0.5 pm in diameter on its surface (Figure 5). These deposits are similar to those reported by Chen and Jakes 10) and Jakes and Wang (7) on cellulosic fibers from the SS Central America. Second, discrete cube shaped particles of varying size up to 1.5 pm in diameter that appear crystalline (Figure 6). Similar particles were found on cotton fibers from the same site 10). Third, irregular shaped discrete particles approximately 2 to 2.5 pm in diameter were observed occasionally. Table II summarizes the elemental composition of the cube shaped discrete deposits, irregular shaped deposits, and continuous pastelike encrustations observed on the marine fibers. 

Table IL Elemental Composition of Surface Deposits and Encrustations Observed on Historic and Marine Silk Fibers...

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