In later weeks, Hall referred to it as his “highway diagnosis.” The principle of it was so simple, so clear and obvious, he was surprised none of them had thought of it before. He was excited as he punched in instructions for the GROWTH program into the computer; he had to punch in the directions three times; his fingers kept making mistakes. At last the program was set. On the display screen, he saw what he wanted: growth of Andromeda as a function of pH, of acidity-alkalinity. The results were quite clear:
