It was Tuesday, February 9, 1971 and Dunedin was stifling. The mercury had hit 28.4degC and the following day would rise to 31.7degC in Dunedin and 38.9degC in Middlemarch. The beaches were crowded and beer consumption, according to one hotel proprietor, had shot up by 20%.
After having conducted a successful moon landing a few days earlier, the Apollo 14 astronauts were headed for splashdown in the southern Pacific Ocean. Keith Holyoake was New Zealand's prime minister, a tin of baked beans cost all of 20 down at the local Four Square and a computer named Elsie made her first Bonus Bonds Prize Draw at the Post Office Savings Bank in Dunedin.
Bonus Bonds, a government-run savings scheme offering monthly cash prize draws instead of interest payments, was set up in 1970. The first 10 prize draws were made by a British Post Office computer known as Ernie (Electronic Random Number Indicator Equipment), but on that sizzling summer day in February 1971 Elsie (Electronic Selection Indicator Equipment) took over.
Elsie, made by British company Plessey, comprised two electronic noise generators which produced white noise pulses. Electronic circuits turned the pulses into random digits. When an eligible bond number (initially nine digits) had been selected it was lit up on neon tubes on Elsie's console, and printed out and punched on to paper tape via several teleprinters.
The University of Otago developed programs to test the output and detect if a draw was not random. Halfway through 1971 a problem was detected. The cause of the problem was mice had been gnawing on Elsie's innards. Some years later, in 1976, a clerk at the Bonus Bonds Centre noticed another serious problem: zero was being selected as the eighth digit way too often. Digit eight had jammed and had to be repaired before the draw could resume.
Bond numbers increased to 10 digits in 1977. This change to 10 digits meant each draw now took 48% longer than before. As the scheme continued to grow prize draws took longer and longer. By 1979 each draw was taking nearly six days and used 14 reels of paper tape. A new, faster Elsie was needed. Elsie II, capable of generating the winning numbers in about an hour and designed and built by NZ Post Office engineers Brian Smellie and Mark Forward, was inaugurated on March 16, 1979.
The redundant Elsie eventually became a museum piece, donated to Toitu Otago Settlers Museum by ANZ Bank, successor to the Post Office Savings Bank, in 1995.
Peter Read is the curator at Toitu Otago Settlers Museum.
