INTO THE STRENGTH OF WROUGHT-IRON PLATES. 
683 
Mean brealdng 
weight in the direc- 
tion of the fibre, in 
tons per square inch. 
Mean breaking 
weight across the 
fibre, in tons per 
square inch. 
Yorkshire plates 
25-770 
27*490 
Yorkshire plates 
22-760 
26-037 
Derbyshire plates 
21-680 
18-650 
Shropshire plates 
22-826 
22-000 
Staffordshire plates 
19*563 
21-010 
Mean 
22-519 
23-037 
Or as 22'5 : 23‘0, equal to about in favour of those torn across the fibre*. 
From the above it is satisfactory to know, so far as regards uniformity in the 
strength of plates, that the liability to rupture is as great when drawn in one direc- 
tion as in the other ; and it is not improbable that the same property would be exhi- 
bited, and the same resistance maintained, if the plates were drawn in any particular 
direction obliquely across their fibrous or laminated struetiire. 
In order however to establish the relative powers of resistance in plates of rolled 
iron, I have endeavoured to tabulate the results, as derived from the preceding expe- 
riments, in such form as will indicate their respective values, and place them in com- 
parison with each other, and also with those made on bars by Telford and Brown. 
The comparisons are made from the Yorkshire plates, as producing the best results ; 
and conceiving them to be a fair average of the strength of rolled iron, I have selected 
them as the standard of comparison. 
Comparative results of rolled iron as derived from experiment, the Yorkshire plates 
being unity. 
Names of Iron. 
No. of 
experiments. 
Mean breaking 
weight in tons per 
square inch. 
Mean breaking 
weight in tons per 
square inch. 
Ratio of the strength of plates 
drawn in the dhrection of the fibre, 
and across it. Also of rolled and 
faggoted bars drawn in the direc- 
tion of the fibre. 
Yorkshire plates 
8 
25-514 
Derbyshire plates 
4 
20-160 
1 : 0-7882 
Shropshire plates 
4 
22-413 
1 : 0-8789 
Staffordshire plates 
4 
20-264 
1 : 0*7946 
Mean 
25-514 
20-945 
1 : 0-8209 
From Mr. Telford andY 
Captain Brown’s expe- > 
26-41 
1 : 1-0351 
riments on bars J 
* In some experiments by Navikr upon the strengths of plates of wrought iron, both in the direction of the 
fibre and perpendicular to it, he found them as 40'8 to 36'4. The new methods of piling thorough bars before 
rolling may however account for the difference, and in a great measure determines the strength of the plate. In 
this country the process of piling is by equal layers of flat bars at right angles to each other, which produces 
great uniformity of strength and texture in the manufacture. At other places there is sometimes a difference 
in the mode of piling, which varies the texture of the plate, and also the strength of the layers are greater in 
one direction than another. 
4 s 2 
