(b. Philadelphia, Pennsylvania, 8 July 1867; d. Washington, D.C., 29 April 1940)
Edgar Buckingham is best known for his early work on thermodynamics and for his later study of dimensional theory. Especially attracted to problems that could not be solved by pure calculation but required experimentation as well, he showed more clearly than anyone before him how the planning and interpretation of experiments can be facilitated by the method of dimensions, later called dimensional analysis.
Buckingham graduated from Harvard in 1887 and received his Ph.D. at Leipzig in 1893. His book on thermodynamics (1900) carried the reader from the simplest facts of temperature measurement through the equilibrium of heterogeneous systems. It was a powerful contribution toward clarifying the subject.
Between 1891 and 1901, Buckingham taught physics at Harvard, Bryn Mawr College, and the University of Wisconsin. He entered government service as an assistant physicist in the Bureau of Soils in 1902, and was employed by the Bureau of Standards from 1905 until his retirement in 1937. His natural ability as a teacher and lecturer was evident in his lectures on technical thermodynamics in the Naval Postgraduate School at Annapolis (1911–1912) and in the graduate program of the National Bureau of Standards (1912–1913). Buckingham served as a technical expert on the Council of National Defense during World War I and as an associate scientific attaché with the United States Embassy in Rome from 1918 to 1919. He was frequently called upon during his years with the Bureau of Standards to advise the Navy Department on steam turbine and propeller research.
Buckingham’s treatise on thermodynamics was followed by fifty or more scientific papers. The subjects included soil physics, properties of gases, blackbody radiation, acoustics, fluid mechanics, and dimensions. Several of his noteworthy papers on dimensional theory, listed in the bibliography, awakened a lively interest in dimensional methods and their practical application.
He pointed out the advantages of dimensionless variables and how to generalize empirical equations. His frequently cited “pi-theorem” serves to reduce the number of independent variables and shows how to experiment on geometrically similar models so as to satisfy the most general requirements of physical as well as dynamic similarity.
Buckingham’s works include An Outline of the Theory of Thermodynamics (New York, 1900); “Physically Similar Systems…”, in Physical Review, 2nd ser., 4 (1914), 345–376; “Windage Resistance of Steam Turbine Wheels”, in Bulletin of the Bureau of Standards, 10 (1914), 191–234; “Model Experiments and the Forms of Empirical Equations”, in Transactions of the American Society of Mechanical Engineers, 37 (1915), 263–296; “Notes on the Methods of Dimensions”, in Philosophical Magazine, 7th ser., 42 (1921), 696–719; see also 48 (1924), 141–145; and “Dimensional Analysis of Model Propeller Tests”, in Journal of the American Society of Naval Engineers, 48 (1936), 147–198.
Mayo Dyer Hersey