Fig. 5. Comparison of ¹³C NMR spectra obtained on M-100 and DM-X300 spectrometers of (A) Diluvial humic acid (HA) from Japan (contact time [CT] = 1 ms), described by Matsuda and Schnitzer (1971); (B) Mangrove Lake HA from Bermuda (CT = 1 ms), described by Hatcher et al. (1983); and (C) HA from Mt. Rainier degraded wood, Washington (CT = 2 ms), described by Hatcher (1987).