The authors carried this study with woods of Quercus serrata Thunb. containing various quantities of water, using iron retort of about 7 L. capacity. To obtain samples of various moisture contents, the woods were treated in three different ways, as follows; (A) Woods were cut down and air-dried ud to such moisture contents as 40%, 30%, 25%, 10%, and less than 10% respectively. (B) Air-dried wood of lower than 10% moisture content were dipped in water to absorb it fully and then air-dried again up to such moisture content as 40%, 30%, and 25%, respectively. (C) Woods freschly cut down were soon dipped in water to absorb it fully. The authors obtained the foollowing results in this study: (1) In yields of the products of the destructive distillation on weight of the samples, charcoal, acids in distilled liquor (mostly acetic acid) and wood-gas (including loss) increased, and distilled liquor (including settled tar) decreased, according as moisture content of the samples decreased. (2) But moisture content of the samples had not any effect on the yields of these products per weight of the absolutely dry samples. (3) According as moisture content of the samples decreased, concentration of acids in distilled liquor increased. (4) Volumetric gravity of charcoal was largest in the case of wood not air-dried after being cut down.(5) In the destructive distillation, water was distilled almost at 100∼150°C in the retort, the wood was decomposed gradually at 150-250°C and then temp-erature rised rapidly, much distilled liquor was run out, and much wood-gas was exhausted at 250-350°C. The wood-gas was composed of CO₂ and CO for the most part at 150-300°C, namely of about 60% CO₂ and 20-30 CO.