The first scientific discipline to engage in a study of artifacts was almost certainly chemistry. A history of chemistry’s early involvement in archaeology would not be complete without mentioning the names of famous chemists such as Martin Heinrich Klaproth (1743-1817), Sir Humphry Davy (1778-1829), Michael Faraday (1791-1867), and Carl Christian
Figure 1 Archaeometry - the link between scientific techniques and archaeological applications.
Traugott Friedemann G(3bel (1794-1851). The primary motivation for their work was curiosity as a consequence of their interest in studying and identifying matter and the changes induced by chemical reactions. The earliest recorded paper to describe a chemical investigation of antiquities was read before the Royal Academy of Science and Belles Letters of Berlin in 1795 by Martin Heinrich Klaproth. Klaproth devised a procedure using gravimetry and used it to measure the compositions of several Greek and Roman coins.
During the first half of the nineteenth century, about 25 reports were published on the quantitative analysis of copper-based coins, glass, and pigments. Among these were a paper by Humphry Davy on the examination of ancient pigments from Rome and Pompeii in which he identified a synthetic pigment later called ‘Egyptian blue’, formed by combining copper, silicon, and natron. Faraday was the first to identify lead as an intentional component in the glaze on ancient pottery. However, it was Gcibel who first explicitly stated that the results obtained from the chemical analysis might be used to answer archaeological questions. Gcibel’s results were published in 1842 in the form of a pamphlet with the very descriptive title: ‘‘On the power of chemistry in identifying peoples of ancient times, or results of a chemical investigation of metallic antiquities, especially those occurring in the Baltic provinces, for the purpose of identifying the peoples from which they came.’’ Because Gobel’s work involved analysis of statistically significant numbers of samples, he was also the first to establish chemical properties for a group of specimens, as opposed to reporting individual analyses.
Another individual who contributed significantly to the characterization of archaeological specimens was the French mineralogist Alexis Damour. Through his studies of jade from different sources around the world, Damour came to recognize the differences between the sources. Damour also published an extensive investigation on the density and chemical composition of stones from known sources with the end view of providing fundamental data useful for determining the place of origin of such objects. Thus, it can be inferred that Damour was the first to recognize the concept of sourcing - proof of origin through similarity of physical and chemical analyses.
During the latter half of the nineteenth century, the character of archaeology began to change from the discovery of buried treasure toward increasing scientific knowledge. This change led to increasing cooperation between archaeologists and chemists. Two individuals who stood out were Marcelin Berthelot and Heinrich Schielmann. Berthelot made it a point to analyze artifacts not only for their chemical identification but also to investigate their significance from the standpoint of the history of early technology. Schielmann, who is recognized for his excavations at Mycenae and Troy, frequently included the results from chemical analysis of materials in his archaeological reports.
During the first half of the twentieth century, advances in the ability to characterize archaeological materials were beginning to gain recognition by archaeologists as useful for studying models of trade and exchange and explaining the changing distribution of materials over time and space. One of the pioneers was Anna O. Shepard who was active in the study of ceramics by petrographic analysis during the 1930s through 1950s. Many will agree that her classic book Ceramics for the Archaeologist set the standard and established a vocabulary for discussing the analysis of ceramics. During approximately the same period of time, Earle Caley was using emission spectroscopy to study the compositions of glass and metal artifacts.
The discoveries of radioactivity by Becquerel in 1896, the atomic nucleus by Rutherford in 1909, and the neutron by Chadwick in 1932 set the stage for the development of several analytical techniques based on atomic and nuclear properties. In 1936, George Hevesy discovered the technique of neutron activation analysis (NAA). But the NAA technique was not ready for routine application in archaeology until 1956, when Robert Oppenheimer assembled a group of archaeologists and chemists at the Princeton
Institute of Advanced Studies to discuss the possibility of applying the method to the study of archaeology. Following the meeting, Edward Sayre and Robert Dodson, chemists from Brookhaven National Laboratory, conducted a study of Samian ware from different locations in Asia Minor, Greece, and Italy using NAA.
The results of the NAA investigation showed that trace element impurity patterns for the pottery within a region were correlated and that different regions could be distinguished from another. The project was judged to be such an outstanding success that it laid the foundations for chemical analysis of thousands of archaeological samples including pottery, obsidian, flint, marble, turquoise, and limestone by laboratories established at Brookhaven National Lab, Lawrence Berkeley Laboratory, the University of Michigan, and elsewhere. Although many of the original NAA labs no longer exist, increases in the use of automation are allowing more samples being analyzed by NAA today than ever. In addition to NAA, other techniques such as X-ray fluorescence (XRF) and proton-induced X-ray emission (PIXE), inductively coupled plasma (ICP), and lead isotope analysis have been employed in artifact characterization studies. Gradual improvements in the analytical techniques over the years have enabled the measurement of greater numbers of elements and isotopes with more sensitivity and better precision.
By the 1980s, techniques from the biological sciences were being employed to analyze organic materials such as bone, waxes, resins, food remains, and textiles. And, during the past decade, surface analytical methods such as laser ablation ICP mass spectrometry (LA-ICP-MS) and scanning electron microprobe (SEM) have become popular techniques for examining glazes, paints, mineral inclusions, etc.
Materials characterization studies have changed the way that archaeologists interpret how trade and exchange operated in the past. They also help to explain the distribution of archaeological material across the landscape, changes in distribution over time, and changes in the economies and organization of societies. It is not unreasonable to estimate that several tens of thousands of archaeological samples are being chemically characterized every year in laboratories around the world for studies of provenance, technology, and authentication.
World History
