ON THE STEENOTH OF PILLAES OF CAST lEON. 
861 
W Ttli 
p”— which expressions the first is represented by and is calculated on two 
suppositions for the value of n\ the other depends on the value of^. From my former 
experiments, was taken as 3'55, and^ as 1‘7 ; and from the experiments in the present 
research, we have w=3-5, and p=l-63, as mentioned before. To assist in computing 
the strength of pillars, according to this last supposition, the two Tables of powers 
of the diameters and lengths of pillars previously given (page 860) have been formed. 
W 
The experiments give the mean value of or as 2085‘2 or 2223‘7 lbs. for the 
strength of a pillar 10 feet long and 1 inch diameter; but for a pillar of 1 foot long and 
1 inch diameter it would be ^xlO^, where 10^=60T19, or 42'658. 
First Summary of Results. 
Results from the Experiments in Tables I. and II. upon pillars of Low Moor Iron, 
No. 2, and Blaenavon Iron, No. 3, the length of each being 10 feet, and the ends 
turned flat and perpendicular to the axis. 
No. of experiment. 
Value of X, or the breaking 
weight of a solid pillar 10 feet 
long and 1 inch diameter, flat 
at the ends, from the formula 
W 
p)3-55_^3'55’ 
Value of X from 
the formula 
W 
J)3'5_^3-5 
EiTor from 
using the 
mean from 
power 3'55, 
in terms of 
the value 
of X. 
Error from 
using the 
mean from 
power 3'5, 
in terms of 
the value 
of X. 
Hollow pillars, from 
2|- to 4 inches ex-*; 
ternal diameter ... 
Solid pillars, inches 
in diameter. 
■ 1 . 
2 . 
3. 
4. 
5. 
6 . 
7. 
. 8- 
11 . 
12 . 
13. 
14. 
lbs. 
220M 
2332-9 
2226-7 
2285-8 
1975-6 
2023-3 
1963-8 
1785-3 
2008-9 
2048-5 
2034-1 
2096-7 
Low Moor, 
No. 2. 
Mean 2085*2 
Blaenavon, No.3. 
Mean 2065*4 
lbs. 
2324-9 
2463-7 
2374-2 
2471-3 
2121-7 
2173-9 
2127-6 
1928-8 
2105-2 
2146-1 
2131-8 
2197*0 
Mean 2223*7 
Mean 2164-4 
1 
'¥4 
1 
'157 
1 
’ll'4 
4-— k- 
18-02 
+ -L 
'32-7 
+ -L 
~l6-2 
+ — 
^ 5-95 
+ -i_ 
'26-3 
-f — 
' 55-8 
-h 
65 
'67 
23 
1 
10^ 
I_ 
15-8 
1_ 
10 
+ -L 
^ 9n»ft 
E 437 
+5 
-f— 
^ 6-54 
"^ 17-8 
H — — 
^27-7 
+ — 
^65-4 
67-4 
In the first two experiments of the preceding summary, the results are perhaps some- 
what too high, though great care was taken to avoid error. In the columns (Experiments 
7 and 8) they are too low. These had been weakened by being turned on the outside 
to reduce their strength, as they had been cast stronger than it was supposed the 
MDCCCLVII. 5 u 
