ON THE STEENG-TH OF PILL AES OF CAST lEON. 
877 
Table I. (continued). 
No. of Experiment. 
j 
Description of PiUar, : Deflection. 
• 10 feet long, and as above. 
Weight 
producing 
the de- 
flection. 
Breaking 
weight, or 
that with 
which the 
pillar sank. 
Value of X from for- 
mula 
W 
'*^-D3-55-d3-55’ 
where W is the break- 
ing weight, D and d 
the external and in- 
ternal diameters, the 
length of the pillar 
being 10 feet. 
Value of X 
from 
formula 
W 
D3'5_(i3-5 
Remarks. 
7. 
Hollow unifonn cylinder 9 ft. 9 in. 
long. inches. 
E.xtemal diameter from 1 q.qq^ 
twelve measurements... j 
Internal diameter from 1 o.iy 
eight measurements ... j 
Weight of pUlar 106 lbs. 10 oz. 
inch. 
•03 
■04 
■07 
■10 
•29 
■48* 
lbs. 
20693 
46271 
74495 
93311 
102719 
112127 
112127, or 
107403 lbs. 
=47^95 tons, 
if the pillar 
had been 
10 feet long. 
lbs. 
1963^8 
21276 
This and the following pillar were cast 
to be 4 inches external diameter, 
and were found so strong as to re- 1 
quire weights which would injure j 
the machinery. They were there- 1 
fore turned outside to reduce their j 
strength, and this, by taking away i 
the hard external surface of the me- 
tal, seems to have produced that ' 
effect in a vei’y great degree. They j 
were cast 9 feet 9 inches long instead , 
of 10 feet, so that they might be 
broken with rounded caps on the i 
ends, which would only have re- 
quired one-third of the weight re- 
quired by pillars with flat ends. , 
Ratio of thicknesses of metal on oppo- : 
site sides in middle ^37 to ^25. 
8. 
Hollow uniform cylinder 9 ft. 9 in. 
long. 
External diameter from! g.g^g 
twelve measurements... j 
Internal diameter at mid- 1 
die by eight measure- 1 3’21 1 
ments J 
Weight of pillar 99 lbs. 14 oz. 
■03 
■05 
•09 
•18 
•24 
20693 
39509 
58325 
77141 
86549 
99720 
99720, or 
955 19 lbs. 
=42^64 tons, 
if the pillar 
had been 
10 feet long. 
1785^3 
1928^8 
Ratio of thicknesses of metal on oppo- 
site sides in middle ■21 to ^39, the 
thin side being the concave one. 
This pillar had many flaws in it. 
9. 
CO 
o 
V 
O 
S- 
CZ 
o 
p 
CO 
^ Hollow pillar, the same as in 
Experiment 5. 
Length, including caps on 
the ends, 10 ft. 2 in. 
■12 
■18 
■26 
■30 
■36 
■42 
■55 
■68 
M6'| 
to ^ 
1-37 J 
20693 
25397 
30101 
32453 
34805 
37157 
39509 
41861 
44213 
44683, or 
45956 lbs. 
= 2051 tons, 
the breaking 
weight of the 
pillar if 
10 feet long. 
10. 
Hollow pillar, the same as in 
Experiment 6. 
Length, including caps on 
the ends, 10 ft. 2 in. 
■14 
■21 
■31 
■47 
■63 
■85 
140 
20693 
•25397 
30101 
34805 
37157 
39509 
41861 
42331 lbs., 
or 43537 lbs. 
= 19^44 tons, 
if the pillar 
had been 
1 0 feet long. 
i 
The hollow pillars in Experiments 5 and 6 had been prevented from being broken 
by a prop, which was made to act on their middle immediately after they had been bent 
beyond their utmost power of resisting. They were then unloaded and reserved for 
another experiment, as below ; after being rendered straight and turned afresh at the 
ends, rounded caps were affixed to the ends, to enable the straining force to be applied 
MDCCCLVII. 5 Y 
