MEMOIR OF THE LATE PROF. E. HODGKINSON, F.R.S. 175 



extensive inquiry, by Mr. Hodgkinson_, " On the Strength 

 of Pillars of Cast Iron and other Materials." 



The object of this inquiry is to supply a desideratum in 

 practical mechanics, which had been pointed out by Dr. 

 Robison and Prof. Barlow. In order to accomplish this, 

 it was necessary to institute a series of expensive experi- 

 ments, more varied and extensive than any which had 

 hitherto been made public. The subject was mentioned to 

 Mr. Fairbairn, who at once, with his characteristic liber- 

 ality, supplied his friend with ample means for investigating 

 experimentally the strength of cast-iron pillars. For this 

 paper the Council for the Royal Society awarded Mr. 

 Hodgkinson the Royal Medal as a mark of their apprecia- 

 tion of his labours, the value and importance of which are 

 confirmed by every engineer's pocket-book in Europe during 

 a period of twenty years. 



The inquiry is naturally divided into two parts, viz. Long 

 PiUars and Short Pillars. 



Long Pillars. 



The first object was to supply the deficiencies of Euler's 

 theory of the strength of pillars, if it should appear capable 

 of being rendered practically useful, and if not, to endeavour 

 to adapt the experiments so as to lead to useful results. 

 For this purpose solid cast-iron pillars were broken, of vari- 

 ous dimensions, from five feet to one inch in length, and 

 from half an inch to three inches in diameter. In hollow 

 pillars the length was increased to seven feet six inches, 

 and the diameter to three inches and a half. 



With pillars of cast iron, wrought iron, steel] and timber , 

 whose length is upwards of 30 times their diameter, the 

 strength of those with fiat ends is three times as great as 

 those with rounded ends. 



Experiments were next made upon pillars with one end 



