THE ROYAL ARTILLERY INSTITUTION 
197 
| No. of experiment. 
Description 
of shot. 
Length in inches. 
Diameter in inches. 
Area in inches. 
Weight laid on in lbs. 
Compression per unit of 
length in inches. 
Pressure per square inch 
in lbs. 
Pressure per square inch 
in tons. 
Work done during the ex¬ 
periment in foot pounds 
per square inch. 
Means of 
ditto. 
Remarks. 
1 
Cast-iron, flat 
ended . 
1-5 
•875 
•6013 
73,428 
•08 
122,115 
54*51 
902-6 
7 5 
Crushed. 
2 
Do. 
1*5 
•83 
•541 
68,052 
•053 
125,787 
56-13 
650-9 
> 4 40 o < 
Crushed. 
3 
Cast-iron, 
round-ended 
1-72 
•85 
•5674 
35,540 
•122 
62,636 
27-96 
899-7 
? QOI .Q 3 
Crushed. 
4 
Do. 
1-72 
•95 
•7088 
40,916 
•139 
67,725 
25-77 
744-1 
> oJil v < 
Crushed. 
6 
Wrought-iron, 
flat-ended ... 
1-5 
•875 
•6013 
94,412 
•193 
157,013 
70-09 
2542-8 
? OAAA .A, 3 
Compressed. 
6 
Do. 
1-5 
•83 
•541 
94,412 
*37 
174,513 
77-9 
4340-1* 
> 4b < 
Compressed. 
7 
Wrought-iron, 
round-ended 
1-72 
•85 
•5674 
75,220 
•225 
132,569 
59-18 
2996-1 
l oonn.A 5 
Compressed. 
8 
Do. 
1-72 
•95 
•7088 
64,468 
;-i68 
90,953 
40-6 
1405-2* 
Compressed. 
9 
Hardened steel, 
1 
flat-ended ... 
1*5 
•83 
•541 
145,756 
1-026 
269,419 120-27 
1608-1 
600 
Compressed. 
10 
Hardened steel, 
round-ended 
1-72 
•85 
•5674 
114,980 
•1162 
202,643 
90-46 
2515-0 
• 00 
Eractured. 
11 
Leaden ball, 
flat-ended ... 
1-5 
•95 
•7088 
7,078 
•393 
9,985 
4-45 
270-9 
• 0 0 
Compressed. 
12 
Leaden ball, 
round ended 
1*72 
•95 
•7088 
7,078 
•400 
9,985 
4-45 
290-6 
Compressed. 
Mr Eairbairn remarks,—• 
“ The mean resistance of the specimens of cast-iron is 800f foot pounds per square 
incli, that of the specimen of steel 2515, or rather more than three times as much.” 
Before giving an account of the experiments which have been made at 
Shoeburyness and Portsmouth bearing on the subject of this paper, it may¬ 
be well to denote the properties which constitute the distinction in cast-iron, 
wrought-iron, and steel; for these three sorts of iron, although all coming 
under the common name of iron are (Dr Percy tells us) “ virtually distinct 
metals, which, in external characters, differ far more from each other than 
many chemically distinct metals.” 
The following definitions are extracted, by permission of the author, from 
Dr Percy's work on Metallurgy :J— 
“ When carbon is absent, or only present in very small quantity, we have 
wrought-iron, which is comparatively soft, malleable, ductile, weldable, easily 
forgeable, and very tenacious, but not fusible except at temperatures rarely attainable 
in furnaces, and not susceptible of tempering like steel; when present in certain 
proportions, the limits of which cannot be exactly prescribed, we have the various 
kinds of steel, which are highly elastic, malleable, ductile, forgeable, weldable, and 
* These experiments On wrought-iron cannot be relied upon, as the socket of the plunger broke 
in both cases. 
f A pressure of one pound exerted through a distance of one foot. 
X Iron and Steel. By John Percy, M.D., P.R.S. 
