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MR. HODGKINSON’S RESEARCHES ON THE STRENGTH OF PILLARS. 
were reduced, one half of the thickness of the rnetal being 1 taken away from the 
pillar near to the ends, and one-fourth, half way between the middle and the ends. 
When no more metal- than this was taken away, the pillars were never broken in the 
reduced parts. The fourth pillar given in this group was a very good casting, and 
the section is represented by W below it. The small piece where the crack is seen, 
broke out, showing very distinctly the position of the neutral line. 
The pillars No. 9. are the first four in Table XI. They were hollow, and the metal 
in them was cast to be all of equal thickness, except that in the discs. The marks 
upon them will show the places in which they broke. These pillars were somewhat 
weaker than uniform hollow cylindrical ones of the same length, thickness and quan- 
tity of rnetal (Art. 48.). 
The two last pillars in No. 3. were of oak (Table XIII.) ; and the second of these 
is intended to show how timber, when much compressed, becomes wrinkled near the 
ends. 
In this Plate the pillars are not drawn of their real lengths, but many of them are 
of half the length compared with the diameter. 
