Creosote removed; the "heavy oil", which sinks; and the "anthracene oil", which when cold is mostly solid and greasy, of a buttery consistence. Creosote refers to the portion of coal tar which distills as "heavy oil", typically between 230–270 °C, also called "dead oil"; it sinks into water but still is fairly liquid. Carbolic acid is produced in the second fraction of distillation and is often distilled into what is referred to as "carbolic oil". Commercial creosote will contain substances from six groups. The two groups occur in the greatest amounts and are the products of the distillation process—the "tar acids",
A Is for Acid about the term "corpus delicti", wrongly assuming it means murder cannot be proven without the presence of a body. He subsequently dreams up what he believes to be the perfect murder and experiments by dissolving mice in sulphuric acid. After learning that Betty gave birth to a daughter and moved away, Haigh travels to London upon his release, where he finds employment as an engineer. After being sacked from his job because of a relationship with his boss's daughter, Gillian Rogers, Haigh sets himself up as an inventor. He bumps into a former employer, Donald McSwan, who has a successful