British Double Summer Time was a Second World War-era extension of the existing Summer Time Act. The existing system involved setting the clocks an hour forward on the last Sunday of March and setting them an hour back on the last Sunday of October, to take maximum advantage of daylight hours.
In winter 1940, Britain did not set the clocks back an hour, and retained the hour's advance of the summer. The clocks were then set forward another hour the following summer, meaning they were two hours ahead of GMT.
Regular Greenwich Mean Time was restored at the end of summer 1945.
This is a covert reference by Pynchon to Operation Paper Clip, an American programme recruiting top Nazi scientists to be smuggled to the United States to aid in the burgeoning technological race against the Soviet Union.
President Truman gave the order in August 1945, though the Joint Intelligence Objectives Agency (JIOA) had been actively recruiting since May of that year. Truman expressly forbade the recruitment of any scientists who had been more involved in Nazi activity than an ordinary citizen. However, the JIOA created false backgrounds and papers for their targets, as well as purging existing records of their affiliations.
The name 'Paperclip' came from the clips used to attach scientists' new identities to their JIOA personnel files.
Wernher von Braun, quoted at the start of Gravity's Rainbow, was one of the most high-level targets of Operation Paperclip. Though he designed the V-2 rockets that dominate the novel, he became a US citizen in 1955, helped the US reach the Moon in 1969. He received the National Medal of Science in 1975.
This is a reference to Helen Duncan (1897-1956), who was imprisoned under the Witchcraft Act in 1944, the second last such case in Britain.
In November 1941, Duncan held a séance in which she described a dead sailor wearing a cap marked HMS Barham, who told her his ship had sunk. This caught the attention of the authorities, as the HMS Barham had indeed been sunk, though this had been kept secret from the public. Duncan's activities as a medium are known to have been fraudulent. Her reference to the sinking was probably an attempt to gain credibility by revealing unknown information. Her source for the intelligence is unknown. The government, afraid that she might have access to details regarding the D-Day invasion of Normandy, managed to secure a conviction under the Witchcraft Act, which prohibited fraudulent 'spiritual' activity.
Duncan was released in 1945 after she promised to stop holding séances, though she continued to do so and was rearrested in 1956 for violating this condition (the Act itself had been repealed in 1951). She died shortly afterwards. A campaign for her posthumous pardon is ongoing.
Wormwood Scrubs Prison is a Category B men's prison located in West London.
It was built in 1874 using convict labour, after the head of the Prison Department, General Sir Edmund du Cane, had seen the Sing Sing Prison in New York.
During the Second World War, the prisoners of Wormwood Scrubs were evacuated, and the prison was taken over by the War Department. It served as a secure operating house for MI5, as well as MI8, the Radio Security Service.
The company was founded in December 1926 as a merger of Brunner Mond, Nobel Explosives, the United Alkali Company and British Dyestuffs Corporation. It developed a number of chemical products, including the dye phthalocyanine, the plastic Perspex, Dulux paints, and polyethylene.
The company was taken over by the Dutch firm Akzo Nobel in 2008.