444 
MR. HODGKIN SON’S EXPERIMENTAL RESEARCHES 
Table VIII. (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 ' 76 — d 3 ' 76 ’ 
where W — the break- 
ing weight, and D, d 
the external and 
internal diameter. 
Remarks. 
14. 
i 
Hollow uniform cylinder. 
External diameter 
Internal diameter bymea- 1 
sure J 
Internal diameter by cal- j 
dilation J 
Mean... 
Weight of pillar, 7 ft. 64- 
long, 59§lbs. 
nches. 
3-36 
2-81 
2-836 
inch. 
•09 
•11 
■13 
•19 
•23 
•27 
•32 
•41 
•50 
•61 
•69 
•81 
MO 
lbs. 
16115 
18667 
21219 
23571 
25923 
28275 
30627 
32979 
35331 
36507 
37783 
39057 
40335 
lbs. 
lbs. 
The thicknesses of the metal, on opposite sides, 
at the place of fracture, were as 19 : 34 ; the 
thinner side being the compressed one. 
40973 
895-02 
2-823 
inches 
15. 
Hollow uniform cylinder. 
External diameter 
Internal diameter bymea- ] 
sure J 
Internal diameter by cal- "1 
dilation J 
Mean... 
Weight of pillar, 7 ft. 6 $ 
long, 7 74 lbs. 
3-36 
2-61 
2-65 
bent. 
■09 
•13 
•15 
•17 
•24 
•30 
•38 
•48 
•59 
•67 
•87 
•90 
107 
3355 
16115 
18667 
21729 
24148 
28986 
33824 
37701 
41632 
43597 
45563 
47528 
48511 
49494 
The thickness of the metal varied as 30 : 43, or 
5 : 7 nearly, the thinner side being compressed. 
50477 
880-11 
2-63 
inches 
1C. 
Solid uniform pillar cast in green 
sand. 
Diameter 2-24 inch. 
Weight 93 lbs. 
It was rounded at the ends. 
bent. 
•005 ? 
•02 
•00 
•05 
•12 
•25 
2141 
5161 
7541 
unloaded. 
15737 
18761 
20273 
This experiment, on a solid cylindrical pillar, is 
given for comparison with the others, which 
were all on hollow ones. 
21281 
1026-6 
17. 
<6 
0 
"ca 
07 
O 
3 
to< 
S 
s 
0 
w 
0 
U 
£ 
Hollow uniform cylinder. 
External diameter H78 inch. 
Internal diameter 1'21 inch. 
Length 4 ft. 9 inches. 
In this casting the metal was nearly of equal 
thickness all round. The value of x or 927"86, 
is reduced by calculation to that of a pillar 
7 ft. 64 inches long, according to the ratio 
obtained in the preceding part of this paper, 
where it was found that the strength varied 
inversely as the l - 7 power of the length. 
This remark will apply to the following pil- 
lars. This casting was not very sound. 
13693 
927-86 
18. 
Hollow uniform cylinder. 
External diameter 2'31 inch. 
Internal diameter 167 inch. 
Length 4 ft. 9 inches. 
This casting was sound, and the thicknesses of 
the metal on opposite sides were as 10 : 21 . 
36382 
1005-3 
19. 
Hollow uniform cylinder. 
External diameter l - 85 
Internal diameter by] 
measure J 
Internal diameter by 1 
calculation J 
Mean... 1'36 
Length 2 ft. 7 inches. 
Weight of 2 ft. 5 inches = 
8 lbs. 15£ozs. 
•35 
32587 
33763 
784-9 
The thicknesses of the metal on opposite sides 
were as 11 : 15. In this pillar the length was 
16$ times the diameter, and the fracture 
took place by flexure as before ; but a wedge 
was formed near the centre, which split the 
pillar at the place of fracture, and seemed to 
be an axis round which it turned. 
