Hodgkinson, Eaton

(b. Anderton, near Great Budworth, Cheshire, England, 26 February 1789; d. Manchester, England, 18 June 1861)

applied mathematics, structural mechanics.

Hodgkinson was one of the largely self-taught British mathematicians of the eighteenth and nineteenth centuries who turned their attention to applied mathematics and applied mechanics. His research and publications were confined almost entirely to the experimental and analytical study of the theory of elasticity and the strength of materials, and he became the foremost British authority in these fields during the second quarter of the nineteenth century.

His early education was first directed toward the study of Latin, Greek, and Hebrew in preparation for the university and a clerical career. He soon displayed a strong distaste for these studies, however, and suffered severely at the hands of a stern schoolmaster. As a result, he was transferred to another elementary school, where his mathematical ability was recognized and fostered. These episodes constituted the full extent of his formal education for he was compelled to devote himself to the assistance of his widowed mother, first in working the family farm in Cheshire, and later, beginning in 1811, when the family moved to Manchester, in operating a pawn-brokerage. Hodgkinson extended his knowledge of mathematics and mechanics through private study, largely of the works of William Emerson and Thomas Simpson. In Manchester he was guided and encouraged by John Dalton; together they studied the work of Euler, Lagrange, and Laplace. Hodgkinson had no sectarian affiliations and displayed no interest in religion.

At the age of thirty-three Hodgkinson read his first paper (published two years later), a study of beam flexure. Although a correct understanding of the distribution of stresses in a flexed beam had been reached by Parent and Coulomb during the eighteenth century, the solution had remained generally unnoticed. In Great Britain it had been presented only by Robison in his Encyclopaedia Britannica article, “Strength of Materials,” and it was from this source that Hodgkinson derived the key principle, namely that in a transversely loaded beam the summation of the tensile and compressive stresses across any section must equal zero. Only with the publication of Hodgkinson’s paper in 1824 did the solution become generally known.

In a later paper (1831) Hodgkinson examined the flexural characteristics of cast iron and showed that the tensile and compressive strengths of that material are unequal; and, accordingly, for the most economical cast-iron I beam and tension and compression flanges should be unequal. His further publications covered a variety of problems in structural mechanics, including dynamical loading of beams, column theory, structural characteristics of wrought iron, and hollow girders. In general, his research was relevant to many engineering problems encountered in the rapidly developing railroad industry and, appropriately, he became in 1847 one of the commissioners appointed to study the application of iron to railway structures. The results of his investigations constituted the primary documents in the “Report of the Iron Commissioners,” which appeared in 1849. During this period he also collaborated with Robert Stephenson and William Fairbairn on the design of the Britannia and Conway tubular bridges.

Hodgkinson became one of the first British autodidacts to receive a university appointment when, in 1847, he was made professor of the mechanical principles of engineering at University College, London.

BIBLIOGRAPHY

I. Ooriginal Works. Hodgkinson’s most influential works include “On the Transverse Strain and Strength of Materials,” in Memoirs of the Manchester Literary and Philosophical Society, 2nd ser., 4 (1824); “Theoretical and Experimental Researches to Ascertain the Strength and Best Forms of Iron Beams,” ibid., 5 (1831); the two investigations he contributed to te Report of the Commissioners Appointed to Inquire into the Application of Iron to Railway Structures (London, 1849); and Experimental Researches on the Strength and Other Properties of Cast Iron (London, 1846).

A list of many of Hodgkinson’s publications is given in Royal Society of London, Catalogue of Scientific Papers (1800–1863) (London, 1869).

II. Secondary Literature. Extensive reviews of many of Hodgkinson’s publications are contained in Isaac Todhunter, A History of the Theory of Elasticity and the Strength of Materials, 2 vols. (Cambridge, 1886). For a long biographical article, see Robert Rawson, “Memoir of Eaton Hodgkinson,” in Memoirs of the Manchester Literary and Philosophical Society, 3rd ser., 2 (1865), 145–204, repr. in Annual Report of the Smithsonian Institution (1868), pp. 203–230.

Harold Dorn