ON THE STRENGTH OF PILLARS. 
447 
Table IX. (Continued.) 
No. of Experiment. 
Description of Pillar. 
Deflection. 
Weight 
producing 
the de- 
flection. 
Breaking 
weight, or 
that with 
which it 
sunk. 
Value of x from for- 
mula 
*- w , 
D 3 55_ d 3.55 
where W = the break- 
ingweight, D, d the ex- 
ternal and internal 
diameters ; and the 
length of the cylinder 
= 7 feet 6'f inches. 
Ratioofthe 
thicknesses 
of the ring 
of metal on 
opposite 
sides at 
place of 
fracture. 
Remarks. 
9. 
Hollow uniform cylinder, same 
as No. 5. last table. 
inches. 
External diameter 2-23 
Internal diameter by mea- 1 ^ ^ 
sure J 
Internal diameter by cal- \ . - - 
culation J 
inch. 
lbs. 
lbs. 
lbs. 
This cylinder was reduced in thickness 
in the same manner, and to the 
same degree, as before. It broke in 
six pieces, in the middle, at one 
of the reduced parts half way be- 
tween the middle and the ends, 
where the diameter was 2 - 12 inches, 
and had both of its ends split. 
In this, and the preceding cases, the 
fracture seems to have taken place, 
first in the middle, and afterwards, 
by reaction, in the other places; 
but it is possible that some crack- 
ing at the ends preceded the rup- 
ture. 
Mean... l - 54 
Length of cylinder 7 ft. 4| inches. 
Weight of cylinder 7ft. 6f inches, 
before reduction 47 lbs. 
40569 
3099-0 
4:9 
10. 
Uniform solid cylinder cast in 
green (moist) sand. 
Diameter D76 inch. 
Length 7 feet 6J inches. 
Weight 56 lbs. 
bent 
bent 
•35 
•65 
4135 
10855 
21219 
22787 
23179 
31155 
With 231 79 lbs. it became bent more 
than an inch, and slipped out of the 
place ; it was afterwards rendered 
straight and replaced ; and it would 
have broken with a less weight. 
11 . 
Uniform solid cylinder cast in 
dry sand. 
Diameter 1*72 inch. 
Length 7 feet 6| inches. 
Weight 53 lbs 8 oz. 
•20 
•23 
•28 
•35 
•44 
•65 
16115 
17235 
18355 
19475 
20595 
21715 
21995 
3207-7 
With the last weight, 21995, the pillar 
slipped from its fixings, as the pre- 
ceding one had done, and when re- 
placed it was broken with a less 
weight than it had borne before. 
The weight, in both this case and 
the last, was so near to what the 
breaking weight must have been, if 
the fracture had been effected as 
usual, that I have not hesitated to 
put down the results as those of 
fracture. 
