166 MEMOIR OF THE LATE PROF. E. HODGKINSON, F.R.S. 



There is a very marked difference in the mathematics 

 of this and his former paper '^ On the Strength of Ma- 

 terials." The great battle between the dots and the d^s 

 had been fought at Cambridge University with earnest- 

 ness on both sideSj and^ chiefly through the invincible 

 courage and inexhaustible armoury of Woodhouse, Pea- 

 cock^ Babbage_, and Herschel, the d's of Leibnitz wrested 

 the victory from the dots of Newton. The effects of this 

 victory, which has produced a great change in the ma- 

 thematical literature of this country, are clearly seen 

 in this paper, the principles investigated in which are 

 applied to the numerical computation of the strength 

 and strains of the Menai and Broughton Suspension- 

 bridges. 



^^ Theoretical and Experimental Researches to ascertain 

 the Strength and best Forms of Iron Beams " (read April 

 2nd, 1830). 



Whether we consider the theoretical exposition of the 

 section of fracture, or the faithfully recorded experiments 

 and their practical deductions, we must regard this paper 

 as the most valuable and original contribution to the 

 history of the strength of materials which this century can 

 boast. There is no work in our language, on the same 

 subject, which contains sounder theoretical views, and 

 there is none which can be more practical than it has been 

 to meet the demands of the engineer and the architect. 

 From the theoretical expositions here given of the neutral 

 line, the experiments to determine the strongest beam were 

 devised and successfully carried out. 



The result was the discovery of the celebrated " Hodg- 

 kinson's Beam," that is, the strongest beam which can be 

 made from a given weight of material and a given length 

 and depth of beam. George Stephenson, who was at this 

 time chief engineer to the Manchester and Liverpool Rail- 

 way Company, took great interest in these experiments. 



