440 
MR. HODGKINSON’S EXPERIMENTAL RESEARCHES 
Table VI. — Pillars enlarged in the middle : ends rounded. 
Experiments to ascertain the Resistance of Pillars of Cast Iron, the Low Moor, No. 3, 
formed in the shape of frustums of double cones, the bases meeting in the middle, 
and the extreme ends left prominent in the centre, that the force might pass 
through the axis. Length of pillar 60^ inches. Plate XV. No. 4, A, B, C, D. 
End diameter. 
Middle dia- 
meter. 
Weight of 
column. 
Breaking weight. 
Mean breaking 
weight. | 
Strength, or 
breaking weight 
of a uniform cy- 
lindrical pillar 
of the same 
weight as the 
mean. 
Gain in parts of 
mean breaking 
weight. 
Remarks. 
inch. 
inch. 
lbs. oz. 
lbs. 
lbs. 
lbs. 
1-01 
1-27 
16 5 
4521 
4521 
3838 
1 
6*62 
J This pillar broke five inches from the middle, where the 
1 diameter was 1‘24. 
1-05 
1-05 
1-03 
1-56 
1-55 
1-56 
20 12 
21 0 
21 6 
21 lbs. 1 oz. 
6453 
7573 
7229 
j>7085 
6205 
1 
8-05 
The last of these broke ten inches from the middle, where 
the diameter was 1-43; and also llj inches from the 
middle at the other end. 
1-04 
1-85 
K) 
CO 
11069 
11069 
9555 
1 
T 31 
f This broke fifteen inches from the middle and toward the 
\ other end. 
1-05 
1-82 
10985 
10985 
/ This broke 16f inches from the end, at a flaw, it is there- 
\ fore not used for comparison. 
1-00 
1-97 
o 
00 
04 
12245 
12245 
f 105971 IS 
) 10344j|© 
1 
6*89 
(" This broke 20'35 inches from the middle, where the depth 
■j of the tensile part was to that of the compressed as 105 
[ : 27. 
The strengths of the uniform pillars, of equal weight with those of variable thick- 
ness, in the Table above, were calculated from the experiments upon the pillars 
whose mean weights are 19 lbs. 11 oz., and 28 lbs. 7 oz., in Table I. : it having been 
shown (Art. 46.) that the strength, where the length is the same, varies as the 1*88 
power of the weight, in pillars with rounded ends. 
