Hayford, John Fillmore

(b. Rouses Point, New York, 19 May 1868; d. Evanston, Illinois, 10 March 1925)

geodesy.

After graduating as a civil engineer from Cornell University in 1889, Hayford joined the U.S. Coast and Geodetic Survey. Except for a brief period (1895–1898) of teaching at Cornell, he remained with the Survey until 1909, when he became director of the College of Engineering at Northwestern University in Evanston, Illinois. At Northwestern, Hayford was an active participant in various public and private commissions and was notable for his stress of the need for mathematics and broad cultural studies in engineering education. His principal scientific achievements, however, occurred during his service with the Survey, in which he succeeded C. A. Schott as head of geodetic work in 1900.

Hayford is an important member of a little-studied scientific tradition. Determining the figure of the earth requires masses of extremely precise observations, a thorough grasp of an extensive body of theory, and great skill and ingenuity in computing—a particularly crucial feature in the period before the development of electronic computers. In his great work, The Figure of the Earth and Isostasy From Measurements in the United States (Washington, D.C., 1909). Hayford stresses the importance of economic factors and efficiency in determining the techniques chosen (p. 46 and passim). His achievements therefore stem not only from scientific knowledge and mathematical skills but also from considerable managerial ability.

By introducing the use of the area method, rather than the arc method, Hayford ended an era in geodesy that dated from the seventeenth century and inaugurated the modern procedure in this field. Hayford was also the first who systematically used observations and calculations of topographical irregularities (up to 4,126 kilometers from each astronomic station) and the first to take isostasy into consideration in arriving at the figure of the earth. In 1924 the Hayford spheroid was adopted as the international spheroid of reference by the International Geodetic and Geophysical Union.

Hayford’s work constituted the first demonstration of the validity of the concept of isostasy. Hayford was, of course, aware of the prior work in isostasy done by J. H. Pratt, G. B. Airy, and C. E. Dutton. Like Pratt—but unlike Airy—he and his successor in the Coast and Geodetic Survey, William Bowie, believed that the isostatic compensation is complete and local; that is, the density of blocks of the earth’s crust varies laterally according to their elevation, so that the elevated land masses are less dense than other land masses and float on the subcrustal matter. Hayford postulated a uniform distribution of isostatic compensations with respect to depth and calculated the most probable value of the limiting depth as 113 kilometers.

These views were not immediately accepted by many geologists. T. C. Chamberlin, for example, had postulated a different distribution of isostatic compensation which yielded a limiting depth of 287 kilometers that, according to his planetesimal theory, was fixed at the time of the creation of the earth. Hayford contended that isostatic compensation had been increasing and was at its highest level at present. Relying on geologic evidence of changes in the surface of the earth, Hayford concluded that the earth was a failing, not a stable, structure.

Chamberlin and others could not conceive of how isostatic compensation, a vertical movement, was reconcilable with the lateral movements postulated for mountain formation and other land forms. In response, Hayford hypothesized horizontal flows of rock far beneath the surface, involving frictional heat and chemical reactions. Chamberlin, who described his approach to cosmology as naturalistic rather than mathematical, was clearly not at ease with Hayford’s reasoning. On the other hand, subsequent research on isostasy has developed a “higher synthesis,” incorporating Hayford’s views while accounting for Chamberlin’s criticisms.

BIBLIOGRAPHY

A full listing of Hayford’s writings is in a useful and uncritical biography by William H. Burger, “John Fillmore Hayford, 1868–1925.” in Biographical Memoirs. National Academy of Sciences, 16 (1933). 279–292. Although Burger frequently refers to Hayford’s personal papers and Northwestern University files of great interest, inquiries to Northwestern, Hayford’s children, and Burger’s widow failed to uncover these documents. The United States National Archives has some Hayford materials in the U.S. Coast and Geodetic Survey records. For his relations with geologists, the T. C. Chamberlin papers at the University of Chicago Library are useful.

See also Chamberlin’s review of the Tittmann and Hayford 1906 report to the International Geodetic Association in “Review of Geodetic Operations in the United States,” in Journal of Geology, 15 (1907), 73–79, and Hayford’s reply, “Comment on the Above Review by Mr. John F. Hayford,” ibid., pp. 79–81. The most elaborate attack on Hayford’s work in isostasy is Harmon Lewis, “The Theory of Isostasy,” ibid., 19 (1911), 603–626.

Nathan Reingold