This accounts for the evaporation loss of volatile components during the weathering of inflammable liquids. The relative volatility data required for the calculation are obtained from the capacity factors of the components in the gas chromatographic analysis. Starting from the gas chromatogram of a weathered sample of a gasoline, the chromatogram of the purported source sample is simulated. Generally, concentration patterns of residue samples can be correlated with those of reference samples, providing the evaporation loss has not exceeded 30 percent. This procedure could allow the tracing back of liquid samples from an arson scene to samples found in the possession of a suspect. 2 figures, 1 table, 20 notes, and 1 appendix (Author abstract)