Sub-Product

A liquid product of the dry distillation of Solid Fuels, such as Coal and Lignite, Shales, Wood, and Peat. The consistency of Tar varies from a readily mobile liquid to a mass that flows with difficulty; it is usually dark brown, but it can be almost black. Tar is a complex mixture of Organic Compounds; its composition depends on the initial material and the method of treatment. The low-temperature (500°-600°C) dry distillation of Coal or Peat—that is, Semicoking—yields so-called Primary Tar. The Coking of Coal yields Coal Tar. The Tar formed by Heat Treating Wood is called Wood Tar.