results given by various formulas. These often vary considerably, so in order that a direct comparison in the tables may be made, this value is obtained for wrought iron plate only, using Trcsidder's formula, v/hich is one of the most trustworthy. The equivalent thickness of Krupp cemented steel armour can be obtained immediately by dividing the tabulated value for wrought iron by a " factor of effect " of 2-t^ to 2-4 for uncapped armour piercing
shot, and about 2'0 for capped armour piercing shell. These factors are dependent on the nature of the projectile and must therefore be taken as approximate.
Tables VIII. -XXII. are obtained from trustworthy sources, but as great secrecy is now observed in many countries there may be a few inaccuracies; in some cases the whole of the data are not available.
Table IX. — French Naval Ordnance, 1910.
Official Designation of Gun.
Calibre.
Weight of Gun.
Weight of Charge.
Weight of Projectile.
Muzzle Velocity.
Muzzle Energy.
Perforation
of Wrought
Iron.
Rate of
firing Rounds.
Propellanl.
305 mm.
274 240
194
1647 .. Q.F. Gunsi64'7 mm. 140, , 100, ,
75
65
47
In. 1201 10-8
9-45 7-64 6-46
6-46 5-44 3-94
2-9
2-57 1-85
Tons.
34
23
12
8
8 4
lb.
ft. 750 562
375 190
115
"5 66
31
14
3-3
Ft. -Sees. 2870 2650 2870 2870 3000
2870 2625
2395 3116 2871 2871
Ft. -Tons. 42,890 27,186
21,445 10,890
7,185
6,568
3.153 1,232
943
503 188
In. 46-0 38-8 37-0 290 263
24-5 200
12-4
14-5 10-8
7-9
Per Minute. 1-5 1-5
2
5
6
6
12
12
15
Smokeless B. Powder
Table X. — German Naval Ordnance.
Official Designation ot Gun.
Calibre.
Weight of Gun.
Weight of Charge.
Weight of Projectile.
Muzzle Velocity.
M uzzle Energy.
Perforation
of Wrought
Iron.
Rate of
firing Rounds.
Propellant.
Q.F. Guns— 28 cm.
24
21, ,
17
15
10-5 „
In. 1 1 02
9-45
8-2
6-7
5-9
4-13
3-42
1-97
Tons. 33-3
25-4
15-75
7-8
4-73 I 645 1-34 0236
ft.
88-2 49-5 43-1 19-83
7-27 4-85 0-66
ft. 529
309 242
132
88
38-35 23-6 3-86
Ft. -Sees. 2854
2740 2526 2887 2461 2297 2789 2165
Ft. -Tons. 29,878
16,086 10,707 7,629 3,696 1,403 1,273
125
In.
40- 2
310 26- 1 26-1
180
12-75
14-7
5-4
Per Minute.
3 5 7 8
10 II
Nitro-
Glycerine
powder
Note. — It is stated that the new German 28 cm. 50 calibre naval gun weighing 43-9 tons fires, with a charge of 291 ft, a projectile of 760 ft with a velocity of 2S71 f.s.
Table XI. — Italian Naval Ordnance, 1910.
Official Designation of Gun.
Calibre.
Weight of Gun.
Weight of Charge.
Weight of Projectile.
Muzzle Velocity.
Muzzle Energy.
Perforation
of Wrought
Iron.
Rate of
firing Rounds.
Propellant.
343
305 254 203
152
120
76
57
47
In.
13-5
12
10
8
6
4-72
3-0
2-24 i-8l
Tons 67-9
51 30 19 5-7
2-1
0-6
0-4
ft.
187-
231- 85
57
17
5
2
6
5
17 1-05 0-67
ft.
1215
850
450 250 100
45 I2-:
6
3-.
Ft. -Sees
2067
2580 2461 2526 2296 2116 2296 2198 2330
Ft. -Tons. 36,050
39,220
19,000
1 1,060
3,655
1,397
457
201
124
In. 340
420
310
27-0
I7-0
II-4
8-5
6-3
5-8
Per Minute.
Strip
} Ballistite
Table XII
— Russian
Naval Ordnance, 19 10.
Official Designation of Gun.
Calibre.
Weight of Gun.
Weight of Charge.
Weight of Projectile.
Muzzle Velocity.
Muzzle Energy.
Perforation
of Wrought
Iron.
Rate of
firing Rounds.
Propellant.
In.
Tons.
ft.
ft.
Ft.-Secs.
Ft.-Tons.
In.
Per Minute.
12 in.
12
59
■•
720
2600
33,730
39-0
Nitro- Cellulose
10 „
10
32
d88
2550
22,003
34-0
8 „
8
14
87
188
2950
11,345
29-5
6 „
6
6-28
50-6
91-5
2118
2,849
14-4
9 pr-
4-2
0-87
4-88
27-75
1226
289
4-2
^r>^"
3-43
0-45
3-1
15-0
1451
219
4-6
Q.F. Guns
i8-5
5'75
91-5
2502
3,970
4-7 „
4-72
2-95
15-4
45-0
2502
1,953
14-6
2-9 .,
0-87
3-53
10-8
2700
546
10-3
1-81, ,
l-8l
0-323
3-3
2003
91-8
4-6