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XXXVIII. Exjperimental Researches on the Strength of Pillars of Cast Iron from various 
Parts of the Kingdom. By Eaton Hodgkinson, Esq., F.R.S., F.G.S., Hon. Mem. 
Inst. Civ. E., Hon. Mem. Soc. Ing. Civ. Paris, and Professor of the Mechanical 
Principles of Engineering in University College, London. 
Eeceived JSTovember 20, 1856, — Eead January 8, 1857. 
Having in the year 1840 oiFered to the Royal Society an extensive research upon this 
subject, which was honoured with the kindest notice of the Society, I felt grateful for 
the reception it had met with ; and though in its preparation it had occupied my leisure 
time for some years, and contained the results of as many as 277 experiments, which I 
had made to prove the conclusions arrived at in it, I was still very anxious to improve 
and extend it. Indeed the importance of the subject would seem to justify every effort 
I could make for the pm’pose, when it is considered that a large portion of the houses, 
warehouses and shops in London, Manchester, Liverpool and throughout the country, 
depend for their principal supports upon iron pillars, which frequently appear very thin 
for the weight they have to bear, and being hollow do not allow us to judge from their 
appearance how small a quantity of metal they have in them, or in other words, whether 
the building is abundantly strong, or is ready to fall down and crush the persons within 
it, as has frequently happened to warehouses and other buildings dependent on iron 
supports. Some of the pillars are made to pass through more than one story, or even 
are based on the foundation, and support an intermediate floor and the roof. 
The importance of the subject, in a practical point of view at least, rendered it 
desirable that a number of pillars of large size should be broken, to obtain data for the 
application of the principles established in the preceding research ; but this was imprac- 
ticable at that time, notwithstanding the hberality of Mr. Fairbaikn, who bore the 
expense of that inquiry. For by Mr. Fairbairn’s lever then used, more than 18 tons 
could not be safely applied, and the iron box or frame in which the pillars were broken 
did not admit pillars of greater length than 7^ feet; but the laborious inquiry in which 
I was afterwards engaged by Mr. Stephenson, for investigating the properties of the 
Menai and Conway tubular bridges (that over the Conway in particular), required larger 
and more powerful apparatus than the preceding, and I can now apply more than three 
times the pressure formerly used, and break pillars of 10 feet long, and any shorter 
lengths, with even more accuracy than before. 
A drawing of the former machine is given with the paper (Philosophical Transac- 
tions, 1840), and of the latter, with my experiments in the Report of the Commis- 
sioners appointed to inquire into the application of Iron to Railway Structures, 1849. 
The principle of both machines is the same ; the present is a single lever, about 17 feet, 
