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kinds, the product of Krupp is generally re- garded as tile best. Krupp armor differs from that previously made, not only in the process of manufacture, but in its chemical constitution. Its exact character is a jealously fiuardcd trade secret, which has been sold at a hi<;h |irice to nearly all the great armor manufacturers of the world, but that it contains a small amount of chromium as well as carbon is now generally understood. Previous attempts to produce chrome steel armor had not been successful, though the trials had been numerous and per- sistent. Nearly all of the armor now applied to ships, except very thin plates, is made by the Krupp process. The Terni Works in Italy, and Schneider in France, have continued the devel- opment of their own processes, which give nearly equal results.

The object of having a hai'd face to armor is to break up projectiles by shock, or so to strain or defonu them as to reduce their penetration. It is particularly efl'ective on oblique impact (i.e. where the projectile strikes at an angle with the plate). To combine hardness with toughness was the aim of armor makers for a quarter of a century, and success was not ob- tained until the advent of nickel steel. Had not the improvement of projectiles and guns kept pace with the development of armor, ships could now be made invulnerable: but both have improved so that the relation of guns and armor is now less favorable to the latter than at almost any time in its history. Nevertheless, armor is absolutely indispensable to the protection of ships and their crews against all classes of gun- fire. The power of good Harvey nickel-steel ar- mor to resist penetration is about equal to that of double the tliickness of wrought iron, and the resisting power of Krupp armor is 10 to 15 per cent, greater. These tigures are for att.ack by ordinary armor-piercing projectiles. Pro- jectiles of this type which are fitted with soft caps (see Pro.iectii.es ) penetrate about as deeply in Krup)) as in Harvey armor, and the gain by the use of caps is equal to a reduction in thickness of 8 to 10 per cent, in Harvey armor and 1.5 to 20 in Krup]3 — that is to say. a capped projectile will perforate a Harvey plate 8 to 10 per cent, thicker, or a Knipp plate 15 to 20 per cent, thicker, than will a projectile not provided with a cap. The penetration in armor of the latest United States guns is seen in the accompanying table:

Calibre of gun	Weight of projectile lbs.	Muzzle velocity, f.s.	Muzzle energy, ft. tons.	Perforation at muzzle
				Harvey nickel steel		Krupp armor
				Capped Projectiles	Uncapped Projectiles	Capped Projectiles	Uncapped Projectiles
3-inch. Mark I	13	2800	709	4.4	3.6	4.4	3.6
4-inch Mark VII.	32	2900	1870	6.7	5.7	6.4	5.6
5-inch Mark V.	60	2900	3503	8.6	7.5	8.4	6.6
6-inch Mark VI	100	2900	5838	10.9	9.3	10.9	7.3
7-inch Mark I	165	2900	9616	13.2	11.8	13.2	10.5
8-inch Mark V	250	2800	13692	15.0	13.6	15.	12.1
10-inch Mark III	500	2800	27204	20.	18.6	20.	17.1
12-inch Mark III	850	2800	46246	25.	23.4	25.	21.7

Perforation at

muzjle. Harvey nickel Krupp o i t^ steel. armor. s o If £ "o 1 ^J ll -I at 23 "ca 43 S:-*^ S-^ C.^3 u ^ — o |.| ao C-J to X ^ 1 s s "£ •^ i" ^£ 6£ 3-inch Mark I. 13 2800 709 4.4 3.6 4.4 3.6 4-inch Maik vri. 32 2900 1870 6.7 5.7 6.4 5.G 5-inrh Mark V. 60 2900 3,503 8.6 7.5 8.4 6.6 6-ini'h Mark VI. 100 2900 5838 10.9 9.3 10.9 7.3 7-inch Mark I. IM 2900 9M6 13.2 11.8 13.2 10.5 8-inrh Mark V. 250 281 K) i:i(;o2 15.0 13.6 15. 12.1 10-inch Mark Til. 500 2S00 27204 20. 18.6 20. 17.1 12-lnch Mark HI. 890 2800 46246 25. 23.4 26. 21.7

The principal armor makers in the United States are the Carnegie Works at Pittsburg and the Bethlehem Steel Company of South Bethle- liem. Other companies have furnished thin, plates.

Another form of armor, not used for ships, but only for fortifications, is made of chilled cast iron, and was developed by Grusou, whose works were located at ilagdeburg-Buckau. Herr Gruson died in 1895, and his establishment was then purchased by Krupp. The metal was a specially excellent low carbon cast iron, chilled in the easting on its outer surface, without ap- parently weakening its tenacity. It is designed and shaped to be used in cujiolas of special dome-like form covering one or more ginis. Wliere weight is of no importance it is a very effective defense. Works for its manufacture in the United States have been established near Phila- delphia.

A full account of the early development of armor by Lieut. E. W. Very, U. S. X., is found in the United States Xai^al Institute, vol. ix.. No. 3 (1883). Numerous other papers of less length, but of much value, appear in later num- bers of the Proeeedings. For additional informa- tion, see Armor and Its Attack by Artillery, Lon- don, 1887, by C. Orde Brown; also, the Annual of the office of Xav'il Intelligence, U. S. Navy, esijecially for the years 1891 and 1892; and Text- Book on Ordnance and Gunnery for Vse at the Naval Academy, by Commander R. R. Ingersoll, U. S. N.

For further information in regard to armor, see Ballistics (under Ballistics of Penetra- tion) ; Ships, Armoued; also Projectiles and Guns, Naval.

AR'MORY (from armor, ultimately from Lat. (1) »!(;, arms). A niilitaiy depot or building set apart for the use of troops, storage of arms and equipment, or purposes of defense. In the l.'nited States the term armory is generally ap- plied to local headquarters for partsof the national guard or militia, which are used for purposes of drill, organization, regimental or departmental ollices, and the storage of all stores and equipment pertaining to the troops occupying them. In many instances they are inagnificeut examples of military architecture, from both the interior and exterior points of view. Equipped with every modern convenience and many lu.xuries, they afford many of the characteristics and ad- vantages of a first-class g^ummasium or social club. Such features, however, are secured gen- erally by the officers and men themselves, and contribute largely to the success and good standing of the corps in its particular com- munity. In ease of local disturbances, the buildings are admirably adapted for defense, or use as a basis of operations. In England and Conti- nental Europe, the name armory is sometimes ap- plied to a museum of military antiquities, as the armory at Warwick Castle. England, or at the Tower of London, which, however, contains a store of modern as well as ancient and mediieval arms and armor: it also, and more generally, ap- plies to that part of an arsenal, barracks, camp, cantonment, or fort where are situated the offices and workshops of the amiorer and his assistants, or are stored supplies of arms and accoutrements. Examples of the latter may be found in every European military post or station.