Art, Archaeology, and Analytical Chemistry A Synthesis of the Liberal Arts Alvin L. Beilby Pomona College, 645 North College Avenue, Claremont, CA 91 711-6338 I n a recent "Provocative Opinion" i n this Journal Freilich (I)in his description of a new general chemistry sequence stated that time should be spent discussing and demonstrating such topics as atmospheric, geological, cosmic, and marine chemistry, biochemistry, polymer chemistry and the chemistries of semiconductors and of the photographic process in order to give students a greater appreciation for the part chemistry plays in their daily lives. Missing from this list are topics which relate chemistry to the humanities and the social sciences, although Freilich does include in his list the history of chemistry and the philosophical and ethical underpinnings of the scientific endeavor. Two fields that do allow for a synthesis of the liberal arts, which I have included in my courses for many years in a n attempt to achieve the same aims as Freilich, are art and archaeology The synthesis of art and chemistry in teaching has been illustrated by many articles in this Journal ( 2 5 ) . Archaeology, on the other hand, has received much less attention as an example to use in the teaching of chemistry. For the past 10-year period I was ahle to find only three articles dealing with archaeology in this Journal (6-8); however, many articles in Analytical Chemistry and Chemical and Engineering News dealing with both art and archaeology have enabled me to include in my wurses examples of the application of chemistry to both of these fields. The contributions of chemistry to archaeology generally are placed in four categories--dating, conservation, prospection, and composition (6).As is seen in articles on art and chemistry (2, 3) the contributions of chemistry to art cover a much broader spectrum. For the purpose of this article the application of chemistry to art will be limited to those applications that are similar to the applications in archaeology.
and journals that should he readily available in chemistry libraries. Dating Techniques Dating techniques provide good examples of the use of several analytical chemistry methods. General summaries of dating techniques are given by Rowe (8)and Taylor (19). Of wurse, the most wmmon dating technique is carbon-14 dating, an example of the use of radiochemical methods and of the use of the accelerator mass spectrometer (AMS) for dealing with very small samples. The breakthrough on sample size with AMS is well-known through the recent dating of the Shroud of Turin (20,211. A summary of the initial investigation by the Shroud of Turin Research Project (STURP) is given in reference (12). The recent report (22) on the use of coral dated by the decay of uranium to calibrate the carbon-14 scale over the past 30,000 years is an excellent example of the importance of calibration in scientific measurements. Another interesting dating technique is thermoluminescence ITL, . . (231. . . Aaood examole of TL datine is eiven in an article on ceramic authentication (24). ~ d a t i n i t e c h n i ~ u e involving electrons trapped in materials after generation by environmental radiation is a n example of the use of electron spin resonance spectroscopyin archaeology (25). Adiscussion on carbon-14 dating can lead directly into a discussion of the use of isotopic ratio methods, in particular, the use of carbon-121carbon-13 ratios. The usual examples of carbon-12lcarbon-13 ratios involve the use of the ratios in bones to give information on diets of ancient humans (26); however, carbon-121carbon-13 ratios along with oxygen-16loxygen-18 ratios have been used also to trace the sources of marble samples (27).
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Instrumental Methods of Analysis Advanced Analytical Chemistry The principal wurse for which I have collected examples of the application of chemistry to art and archaeology has been the advanced analytical chemistry course. A perusal finds essentially of a typical instrumental analysis text (9), no applications of analytical chemistry to art or archaeology except for a mention of the dating of rocks by argon40largon-36 ratios as an example of the use of mass spectrometry and of the authenticating of paintings and other objects of art by neutron activation analysis. In this wurse I emphasize the wmparison of analytical methods (10).Examples involving art and archaeology have proven useful in this approach to the teaching of analytical chemistry. Two cover story articles in Chemical and Engineering News (11-12) serve as excellent introductions to art, archaeology, and analytical chemistry. The continuing series on Archaeological Chemistry i n Advances in Chemistry (13-16) provides many specific examples. A specific report in instrumental analvsis in art and historv (17) a .~.o e a r e d recently. Agood source on the appllcatlons of chemistry to archaeolom is Goffer's book. Archoeolo~rcolChemistry (18).All tKi references given .in this artsle are in books
Examples of the application of most instrumental methods of analysis in art and archaeology are readily available. Some examples provide excellent illustrations of the need to use several analytical methods to solve a particular problem. A list of examples that have been used by me is given in the table. This list is by no means exhaustive and other exam~lescan be found in other references rriven in this article. A comparison of analytical methods in archaeololcal chemistw has been eiven bv Meschel(281. the table-deals k i t h authenticity The last example studies of the Vinland Man and illustrates how controversy can arise in the interpretation ofanalytical data. The eeneral stow of the Vinland Mao first aooeared in Analvtycal chemistry in 1976 (38). In chis p a p e r ~ a l t e ~r c ~ r o " n e described how he came to t h e conclusion t h a t Yale University's Vinland Map, which was purportedly drawn in 1440 and which shows a large island west of Greenland identified as Vinland, was a clever forgery. Using optical and electron microscopy he was ahle to show in the ink lines the presence of anatase (TiOz) whose presence as a precipitated pigment would have been impossible before about 1920. In 1987, however, Cahill et al. (39) reported
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Volume 69 Number 6 June 1992
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Applications of Instrumental Methods of Analysis in Art and Archaeology Example Old Master Paintings: A Study of the Varnish Problem FT-IR in the Service of Art conservation
Analysis of Organic and Inorganic Compounds in Paintings
30
Analysis of Dyes and Pigments
31
Characterization of Modern and Ancient Papyrus Characterizarion of Pup e Dyes n Ponery Snerds
32
Thermal Methods Mass Spectrometry FT-IR Spectroscopy E ectron Spectroscopy
Proton- nduced X-Ray Emission
33
Analysis of River Sediments for Trace Metals and Minerals ldentification of Ancient Resins to Determine Sources
34
Neutron Activation Analysis X-Ray Spectroscopy Energy-Dispers;veX-Ray Fluorescence Spenroscopy
Trace Metal Analysis of Obsidian Samples
36
Analysis of the Composition of the Bell Alloy
37
Microscopy Proton Induced X-Ray Emission
Analysis of Ink
that titanium was present only in trace amounts as determined by particle-induced X-ray emission (PIXE). ~ c ~ r o n e - & ereplied n in a paper that gave more details than his original paper and discussed the important distinction between instruments used for trace analysis and ultramicroanalysis techniques using very tiny samples (401.McCrone does not question the data &+n hy Cahlll et al. for the amount of titanium found by PIXI.: but states that the amount re~resentsa "trace comoonent" of a laree parchment area but not a trace component of the ink; whereas, he states that he found titanium as a major component of an ultramicro sample of the ink.Recently Towe (41) from an examination of both Cahill et al.'s and McCmne's reports concluded that the studies of Cahill et al. did not invalidate McCmne's basic conclusion but to the contrary actually supported McCrone's original interpretation of the document as a modem forgery. This case study of the Vinland Map, hence, is an excellent example of how controversy can arise on proper use of information obtained by analytical methods to describe an object under study.
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General Chemistry and Environmental Chemistry To eive our eeneral chemistm students a taste of "real" chemkry witG the hope of attracting students to the study of chemistry, our faculty members present "guest" lectures during the course on their research at a level appropriate for general chemistry students. In place of a research lecture I have sometimesgiven a lecture on "Art, Archaeology, and Chemistry". This lecture includes many of the examples presented above for the Advanced Analytical Chemistw course. As much as possible the examples refer to topics siudied in our ~ e n e r a Chemistry l course. For example, since one of our laboratory experiments is a simple neutron activation analysis experiment (421,the use of neu438
29
FT-iR Spectroscopy
ldentification of a Late Bronze Age Resin
The Liberly Bell: Composition of the Famous Failure The Vinland Map
Determination of the Changes in Varnishes with Aging
Unmvering the Secrets of the Neutron Activation Analysis Ancient Nile X-ray Powder Diffraction
Trade in Ancient Peru Traced with Obsidian
Reference
UV-Visible Spectrophotometry Gel Permeation Chromatography
The Bust of Nefertiti Papyrus: The Paper of Ancient Egypt Royal Purple Dye: Tracing Chemical Origins of the industry
Application
Method
Journal of Chemical Education
35
3 8 41
tmn activation analysis for trace analysis in archaeological samples is an obvious topic. Other topics, such as conservation of objects ( 4 3 4 7 )are mentioned also in order to give a more complete picture of the contributions of chemistry to art and archaeology. Finally, to include an additional liberal art, music, mention is made of the chemistry of a Stradivarius violin (48). Since many of the articles referred to in this article are cover stories, a series of slides to illustrate this lecture was easily prepared. Students have commented that the lecture is interesting and that their views of chemistry are expanded. A similar lecture on "Art, Archaeology, and Chemistry"is also appropriate in a course on environmental chemistry for nonscience majors, which is a general education course. I have given this lecture as the last one of the course to show the students that the chemistry that they learned with respect to the environment can be applied to other areas. For example, since radioactivity is covered tboroughly in environmental chemistry, carbon-14 dating as an application of radioactivity is a logical topic; trace metals in the environment leads naturally into the use of trace metal analysis of archaeological samples. Nonscience maior students have resoonded oositivelv to the lecture. The lecture has proven to be an excellent way to increase the appreciation of the contributions of chemistry to society. Conclusion At present chemistry suffers from a negative image pmblem. The inclus~onof examvles of the avvlicat~onof chemistry to art and archaeology in chemist&courses of alllevels from the general education course for nonscience majors to theadvanced analytical chemistry course can help to give chemistry a positive image and to relate chemistry better to other liberal arts. In his editorial for the ar-
