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Man's use of illuminants in lamps or as torches to extend the working day and range of environments accessible to him would have been a major technological advance in human civilisation. The most obvious evidence for this in the archaeological record comes from pottery and stone vessels showing sooting due to the use of a wick in conjunction with a lipid-based fuel or illuminant. A wide range of potential fuels would have been exploited depending upon availability and burning requirements. Reported herein are the results of chemical investigations of a number of lamps recovered from excavations of the site of Qasr Ibrim, Egypt. Gas chromatographic, mass spectrometric and stable carbon isotopic analyses of both free (solvent extractable) and 'bound'(released from solvent extracted pottery by base treatment) lipids have revealed a wide range of saturated fatty acids, hydroxy fatty acids and alpha, omega-dicarboxylic acids. Examination of the distributions of compounds and comparisons with the fatty acid compositions of modern plant oils have allowed a range of fats and oils to be recognised. Specific illuminants identified include Brassicaceae (Cruciferae) seed oil (most likely radish oil, Raphanus sativus), castor oil (from Ricinus communis), animal fat, with less diagnostic distributions and delta(13)C values being consistent with low stearic acid plant oils, such as linseed (Linum usitatissimum) or sesame (Sesamum indicum) oils. The identifications of the various oils and fats are supported by parallel investigations of illuminant residues produced by burning various oils in replica pottery lamps. The findings are entirely consistent with the classical writers including Strabo, Pliny and Theophrastrus.

The chemical analyses of "bog butters" recovered from peat bogs of Scotland were performed with the aim of determining their origins. Detailed compositional information was obtained from "bog butter" lipids using high temperature gas chromatography (HTGC) and GC-mass spectrometry (GC-MS). The results indicate the degree to which "bog butters" have undergone diagenetic alterations during burial to form an adipocere like substance, consisting predominantly of hexadecanoic (palmitic) and octadecanoic (stearic) acids. GC-combustion-isotope ratio MS (GC-C-IRMS) was used to determine delta13C values for the dominant fatty acids present, revealing for the first time that "bog butters" were derived from both ruminant dairy fats and adipose fats. The results are compared and contrasted with modern reference fats and adipoceres produced in vitro.