xii 



turn for languages, and it was determined to send him to the pri- 

 vate school in Northwich to learn mathematics, to which he had 

 shown a strong inclination. He seems to have profited greatly by 

 the instruction he received there, for in after-life he often expressed 

 his gratitude to his early master, Mr. Shaw, for laying the founda- 

 tion of his future mathematical acquirements. 



In 1811 his mother and family removed to Manchester, where 

 Mr. Hodgkinson assisted his mother in carrying on business, by 

 which she eventually earned a competency. In Manchester he had 

 full scope to follow the bent of his mind for mathematical and phy- 

 sical pursuits. Here also he made the acquaintance of various 

 eminent persons distinguished for their scientific attainments or 

 manufacturing and engineering skill ; and, following the example of 

 some other young men of his acquaintance who were desirous of im- 

 provement, he became a pupil of Dr. Dalton, then a private teacher 

 of mathematics in Manchester, and read with him the works of La- 

 grange, Laplace, Euler, and Bernoulli. The friendship thus begun 

 continued uninterruptedly until Dr. Dalton 5 s death. 



The erection of the factory of Phillips and Lee first gave occasion 

 to Mr. Hodgkinson' s experimental inquiries into the strength of 

 materials used in construction, which, amongst other results, led him 

 to propose a new form of cast-iron girder. He discovered that cast 

 iron resists compression with an energy nearly six times as great as 

 that with which it resists extension; and he accordingly recom- 

 mended a form of cross section, in which the upper and lower 

 flanges present sectional areas corresponding with the power of re- 

 sistance to compression and extension respectively j and this form 

 has now been universally adopted. At the works of Messrs. Fair- 

 bairn and Lillie, then rising engineers, Mr. Hodgkinson obtained the 

 requisite means and facilities for making his experiments. 



In 1840 Mr. Hodgkinson communicated to the Royal Society a 

 memoir, entitled "Experimental Researches on the Strength of 

 Pillars of Cast Iron and other Materials," which was published in 

 the 'Philosophical Transactions' for 1840, and obtained for its 

 author the award of the Royal Medal for the year 1841. The re- 

 sults of further inquiries were given in a later paper, published in 

 the 'Philosophical Transactions' for 1857. He was elected a 

 Fellow in 1841. The formulae he deduced for calculating the 



