()80 
MR. FAIRBAIRN’S EXPERIMENTAL INQUIRY 
Experiments to ascertain the Strength of Plates, Sjc. 
In the following experiments all the plates were of uniform thickness, and of the 
form exhibited in fig. 2 in the column of remarks ; the ends had plates riveted to 
them on both sides to render them inflexible; they had holes, 0, 0, bored through 
them perpendicular to the plate, in order to connect it by bolts, with the apparatus 
for tearing it asunder in the part A B, which was made narrower than the rest. The 
centres of the holes 0, 0 were in a direct line through the middle between A and B*. 
Table I. Strength of Plates. — Low Moor Yorkshire Iron. 
No. 
of 
exp. 
Description of plate 
and dimensions in the 
middle. 
1 . 
Drawn in the di- 
rection of the fibre. 
Area of section 
2. 
in middle 
2‘0t)X'22 = ‘44in. 
3. 
4. 
Same iron drawn 
across the fibre. 
Area of section 
1 
2-00 X ‘22 =‘44 in. 
Weight 
laid on in 
lbs. 
24,043 
25,531 
23,571 
24,747 
25,923 
Reduced dimensions in 
middle of plate through 
weights laid on. 
1-96 X -21 
1-89X-19 
Reduced. 
1-93X-18 
1-94X-18 
Breaking 
weight 
in lbs. 
25,531 
24,747 
25,923 
Mean breaking weight 
in lbs. 
25,400, or 25 ‘77 tons per 
square inch. 
Remarks. 
Fig. 2. Plan and section of the plates, 
the line AB being that of the fracture. 
All the plates were laminated as if formed 
of three or more plates, the external ones 
being thinner than the internal onest. 
In the last experiment there was a dis- 
union between the lamina which admitted 
the point of a penknife. 
23,179 
24,355 
25,923 
27,099 
Altered. 
1- 99X-215 
2- 2x-i9‘ 
27,099 
27,099, or 27‘49 tons per 
square inch. 
This, it will be seen, did not break at 
the narrowest place. 
Table II. Strength of Plates. — Low Moor Yorkshire Iron. 
No. 
of 
exp. 
Description of plate 
and dimensions in the 
middle. 
Weight 
laid on in 
lbs. 
Reduced dimensions in 
middle of plate through 
v.'eiglits laid on. 
Breaking 
weight 
in lbs. 
Mean breaking weight 
in lbs. 
Remarks. 
5. 
6. 
Same iron as in 
Table I., drawn 
across the fibre. 
Area of section 
2 00 X '22 = ‘44 in. 
24,355 
26,315 
23,571 
Stretching. 
21-5 x -20 
2-25 X -20 
26,315 
23,571 
25,662, or 26‘037 tons 
per square inch. 
The form and size of speeimen as before, 
fig. 2. 
In these experiments it was observed, 
as in No. 4. in the preceding Table, that 
the plate did not break at the narrowest 
part, a circumstance the more anomalous, 
as there did not appear to be anything in 
the apparatus to cause it. 
7. 
Same iron, thicker 
plates, drawn in di- 
rection of fibre. 
Area of section 
2-00 X -26 = -52 in. 
27,099 
25,923 
Thickness '25 
1-96X-24 
27,099 
25,923 
Very uniform in texture. 
The fracture of this specimen showed a 
great want of regularity; about one-third 
of the area had the appearance of steel. 
All the other i)lates appeared to be uni- 
form, but laminated, as mentioned before. 
• 
26,511 , or 22‘76 tons per 
square inch. 
* For the appearance of the fractures see Plate LV. 
t Nearly the whole of the plates manufactured in this country are laminated, owing to the manner in which 
the shingles are formed, by piling a number of flat bars one upon another, whicli are made larger or smaller 
according as the plate may be required heavier or lighter. 
