Creosote mixed with coal-tar creosote, or fortified with pentachlorophenol. Water-gas-tar creosote is also derived from petroleum oil or shale oil, but by a different process; its distilled during the production of water gas. The tar is a by-product resulting from enrichment of water gas with gases produced by thermal decomposition of petroleum. Of the creosotes derived from oil, it is practically the only one used for wood preservation. It has the same degree of solubility as coal-tar creosote and is easy to impregnate into wood. Like standard oil-tar creosote, it has a low amount of tar acids and tar bases, and
Cedar oil was laid in natrum or natron—a fixed alkali—for the prescribed period, after which the cedarwood oil, which had dissolved the soft organs, was released; and the body, its flesh dissolved by the natron, was reduced to preserved skin and bones. Until the development of synthetic immersion oil in the 1940s, cedarwood oil was widely used for the oil immersion objective in light microscopy. It is still sometimes also used to clarify emeralds. Cedar leaf oil from "Cedrus atlantica" does not contain thujone. Cedarwood oil is a mixture of organic compounds considered generally safe by the FDA as a food additive