Progressive extraction consists of partial extractions of a single coal sample carried out consecutively with fresh batches of a single solvent. Progressive extraction of coal with pyridine has shown, by mass spectral and other analyses, that different constituents predominate at different stages of the extraction. Alkylbenzenes and phenols are prominent in the first extract; polynuclear aromatics are mainly extracted later. The order of extraction is important in the mechanisms of extraction of coals. Quantitative infrared absorption shows higher amounts of ch bonds in the extracts than in the residues. Also, all of the spectral bands of the extracts are more intense and better defined than the bands of the residues.