vitamins in health was being studied, and scientists wanted to identify Vitamin A-rich foods to keep soldiers healthy. Previous methods involved feeding rats for several weeks, then performing a biopsy to estimate Vitamin A levels. The DU spectrophotometer yielded better results in a matter of minutes. The DU spectrophotometer was also an important tool for scientists studying and producing the new wonder drug penicillin. By the end of the war, American pharmaceutical companies were producing 650 billion units of penicillin each month. Much of the work done in this area during World War II was kept secret until after the war. Infrared Beckman and his company were involved in a number of secret projects. There was a critical shortage of rubber, which was used in jeep and airplane tires and in tanks. Natural sources from the Far East were unavailable because of the war, and scientists sought a reliable synthetic substitute. Beckman was approached by the Office of Rubber Reserve about developing an infrared spectrophotometer to aid in the study of chemicals such as toluene and butadiene. The Office of Rubber Reserve met secretly in Detroit with Robert Brattain of the Shell Development Company, Arnold O. Beckman, and R. Bowling Barnes of American Cyanamid. Beckman was asked to secretly produce a hundred infrared spectrophotometers to be used by authorized government scientists, based on a design for a single-beam spectrophotometer which had already been developed by Robert Brattain for Shell. The result was the Beckman IR-1 spectrophotometer. By September 1942, the first of the instruments was being shipped. Approximately 75 IR-1s were made between 1942 and 1945 for use by the US synthetic-rubber effort. The researchers were not allowed to publish or discuss anything related to the new machines until after the war. Other researchers who were independently pursuing the development of infrared spectrometry, were able to publish and to develop instruments during this time without being affected by secrecy restrictions. Beckman had continued to develop the infrared spectrophotometer after the release of the IR-1. Facing stiff competition, he decided in 1953 to go forward with a radical redesign of the instrument. The result was the IR-4, which could be operated using either a single or double beam of infrared light. This allowed a user to take both the reference measurement and the sample measurement at the same time. Other secret projects Helipot At the same time that Beckman was approached