his own life). Anson denies the murder, but Doheny then tricks Anson into revealing that he knows about the attempt on Brade's life. Anson confesses to murdering Ralph and attempting to murder Brade. Background science The story hinges on two chemical facts. First, the victim Neufeld was in the habit of sniffing at the open neck of a flask in order to check that a reaction was occurring. Generally chemists must regard all chemicals as poison, but this habit was common practice and would have been safe with the chemicals he intended to use. Substituting cyanide for acetate in the acidic solution produced hydrogen cyanide gas, which killed him. (However, the actual lethal dose of the volatile gas would be substantially higher.) Second, valves on oxygen cylinders are never lubricated with oil, because oxygen under high pressure reacts with hydrocarbons to produce explosive ozonide compounds. Brade notices the oil on the valve in time to save his life. Doheny tricks Anson by pretending to turn on the oxygen in his presence, causing him to warn Doheny to stop, revealing that he knew about the oil. Brade, however, had already cleaned the valve to remove the oil. (A similar mechanism of murder appeared in Asimov's 1957 story "The Dust of Death".) Characters Louis Brade – an assistant professor of organic chemistry. Doris Brade – his wife. Ralph Neufeld – a paranoid research student of Brade. From Europe. Survivor of "something unpleasant" in which father and sister were killed. Cap Anson – an organic chemist and Brade's former teacher. Roberta Goodhue – another research student of Brade. Merill Foster – an assistant professor of organic chemistry. Colleague of Brade. Otto Ranke – a physical chemist. Colleague of Brade. Arthur Littleby – head of Brade's department. Jack Doheny – a policeman. Adaptations Formula of Death (2012), TV movie directed by Behdad Avand Amini References External links 1958 American novels American mystery novels Mystery novels by Isaac Asimov Avon (publisher) books