Other projects led to compilations of archival data with enormous scientific impact. The MIT Wavelength Tables did nothing less than determine the characteristic light emitted by each element in gaseous form and at high temperatures-hydrogen, oxygen, and the 100-odd others that make up the universe. For example, hydrogen emits ultraviolet radiation and mercury a red glow under those conditions. Knowing the wavelengths of the light allows scientists to unequivocally identify the matter that emitted it, no matter how far away. What we know of the birth, death, and constitution of stars comes from analyzing their light.
Similarly, the WPA Mathematics Tables Project, conducted in collaboration with the Bureau of Standards, extended the quantitative language that scientists use to describe the world. Over centuries of analysis, certain functions have proven essential to the mathematical vocabulary. For example, the recurring peaks and valleys of the sine wave describe the repetitive vibrations common in nature that form waves of water, sound, and light. Other examples include the exponential function, which describes extremely rapid physical change, and Legendre functions, named for the eighteenth-century French mathematician who first explored them, which describe electric fields and quantum behavior.
In 1938, when the mathematics project began, its aim was to calculate these useful functions and publish the results in tabular form. A contemporary article characterizes the project’s computational facility as the largest ever established. It used some 150 electrically powered machines, which added and subtracted numbers the same way an automobile odometer works, with rotating gears whose positions represent numbers and interlock so that results can “carry” from one column to the next. Some 250 WPA-supported staff worked among the slowly churning electromechanical monsters, with their characteristic “chinga-ching” sounds. The employees, who were known as “computers,” checked the results and transferred them from one machine to another, since no single machine could calculate the functions all by itself. The effort continued from 9 a. m. to midnight five days a week, year after year. By 1942, the project had published 12 volumes of tables and had also performed secret military calculations.
Today, of course, printed mathematical tables no longer enjoy brisk sales; people can instantly determine functions using calculators and electronic computers. But during the WPA era-before 1944, when Harvard University researchers built the electromechanical Mark I computer, which followed stored instructions, and before University of Pennsylvania scientists completed the first programmable electronic digital computer in 1946-the development of the tables promised a significant boon to science.