Yield of wood-vinegar prepared from the treated wood tended to increase, and yield of charcoal indicated opposite tendency, but yield of wood-tar was almost constant.

Any of various thick, dark, sticky substances obtained from the distillation residue of coal tar, wood tar, or petroleum and used for waterproofing, roofing, caulking, and paving.

Wirtgen is a leader in making machines that recycle tar and grit from old roads to be relaid as smooth new ones, as is Leitz in making wood-processing tools.