A page from the log book recording testing of the MK II computer, the Aiken Relay Calculator, at Harvard University just prior to delivery to Dahlgren. Technician Bill Burke was searching for the cause of a computation error in the machine on the afternoon of Sept. 9, 1947. He traced the error to a moth caught in the relay. He removed the moth, checked to see if the computer worked properly, and taped the moth into the daily maintenance log book.