Recently, the high resolution nuclear magnetic resonance (NMR) method has been adopted in the studies on the constitution of natural coal. H. Tsukashima carried out the investigation on an artificial coalification process, with Submerged Wood as the starting raw material. The Submerged Wood is found at Uozu, Toyama Prefecture. In his previous papers the composition of Submerged Wood was examined and the cellulose, lignin and humic acid etc. in the artificial coals that were prepared from the Submerged Wood, were measured by various analytical methods, and several reactions in the initial stage of the coalification process were explained. The present report deals with the examination of the structural features of the pyridine extracts of the Submerged Wood and artificial coals therefrom; a study based upon their hydrogen distribution. The NMR spectra of the pyridine extracts of the Submerged Wood and of the artificial coals were compared with NMR spectra of the pyridine extracts of natural coal, reported by G. Takeya et al
