Macintosh found that naphtha - a volatile, oily liquid created in the distillation the aforementioned coal tar, as well as petroleum - could be used to waterproof fabrics.

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.

Two methods of distillation crystallization method and gas chromatography to determine the naphthalene content in coal tar oil were introduced.