EXPLOSIVE Sh.e.l.lS
The word "bomb" comes to us from the French, who derived it from the Latin. But the Romans got it originally from the Greek _bombos_, meaning a deep, hollow sound. "Bombard" is a derivation. Today bomb is p.r.o.nounced "balm," but in the early days it was commonly p.r.o.nounced "b.u.m." The modern equivalent of the "b.u.m" is an HE sh.e.l.l.
The first recorded use of explosive sh.e.l.ls was by the Venetians in 1376. Their bombs were hemispheres of stone or bronze, joined together with hoops and exploded by means of a primitive powder fuze. Sh.e.l.ls filled with explosive or incendiary mixtures were standard for mortars, after 1550, but they did not come into general use for flat-trajectory weapons until early in the nineteenth century, whereafter the term "sh.e.l.l" gradually won out over "bomb."
In any event, this projectile was one of the most effective ever used in the smoothbore against earthworks, buildings, and for general bombardment. A delayed action sh.e.l.l, diabolically timed to roll amongst the ranks with its fuze burning, was calculated to "disorder the stoutest men," since they could not know at what awful instant the bomb would burst.
A bombsh.e.l.l was simply a hollow, cast-iron sphere. It had a single hole where the powder was funneled in--full, but not enough to pack too tightly when the fuze was driven in. Until the 1800"s, the larger bombs were not always smooth spheres, but had either a projecting neck, or collar, for the fuze hole or a pair of rings at each side of the hole for easier handling (fig. 41). In later years, however, such projections were replaced by two "ears," little recesses beside the fuze hole. A pair of tongs (something like ice tongs) seized the sh.e.l.l by the ears and lifted it up to the gun bore.
During most of the eighteenth century, sh.e.l.ls were cast thicker at the base than at the fuze hole on the theory that they were (1) better able to resist the shock of firing from the cannon and (2) more likely to fall with the heavy part underneath, leaving the fuze uppermost and less liable to extinguishment. Muller scoffed at the idea of "choaking" a fuze, which, he said, burnt as well in water as in any other element. Furthermore, he preferred to use sh.e.l.ls "everywhere equally thick, because they would then burst into a greater number of pieces." In later years, the sh.e.l.ls were scored on the interior to ensure their breaking into many fragments.
FUZES
[Ill.u.s.tration: Figure 42--NINETEENTH CENTURY PROJECTILE FUZES.
a--Cross-section of Bormann fuze, b--Top of Bormann fuze, c--Wooden fuze for spherical sh.e.l.l, d--Wood-and-paper fuze for spherical sh.e.l.l, e--Percussion fuze.]
The eighteenth century fuze was a wooden tube several inches long, with a powder composition tamped into its hole much like the nineteenth century fuze (fig. 42c). The hole was only a quarter of an inch in diameter, but the head of the fuze was hollowed out like a cup, and "mealed" (fine) powder, moistened with "spirits of wine"
(alcohol), was pressed into the hollow to make a larger igniting surface. To time the fuze, a cannoneer cut the cylinder at the proper length with his fuze-saw, or drilled a small hole (G) where the fire could flash out at the right time. Some English fuzes at this period were also made by drawing two strands of a quick match into the hole, instead of filling it with powder composition. The ends of the match were crossed into a sort of rosette at the head of the fuze. Paper caps to protect the powder composition covered the heads of these fuzes and had to be removed before the sh.e.l.l was put into the gun.
Bombs were not filled with powder very long before use, and fuzes were not put into the projectiles until the time of firing. To force the fuze into the hole of the sh.e.l.l, the cannoneer covered the fuze head with tow, put a fuze-setter on it, and hammered the setter with a mallet, "drifting" the fuze until the head stuck out of the sh.e.l.l only 2/10 of an inch. If the fuze had to be withdrawn, there was a fuze extractor for the job. This tool gripped the fuze head tightly, and turning a screw slowly pulled out the fuze.
Wooden tube fuzes were used almost as long as the spherical sh.e.l.l. A United States 12-inch mortar fuze (fig. 42c), 7 inches long and burning 49 seconds, was much like the earlier fuze. During the 1800"s, however, other types came into wide use.
The conical paper-case fuze (fig. 42d), inserted in a metal or wooden plug that fitted the fuze hole, contained composition whose rate of burning was shown by the color of the paper. A black fuze burned an inch every 2 seconds. Red burned 3 seconds, green 4, and yellow 5 seconds per inch. Paper fuzes were 2 inches long, and could be cut shorter if necessary. Since firing a sh.e.l.l from a 24-pounder to burst at 2,000 yards meant a time flight of 6 seconds, a red fuze would serve without cutting, or a green fuze could be cut to 1-1/2 inches.
Sea-coast fuzes of similar type were used in the 15-inch Rodmans until these big smoothbores were finally discarded sometime after 1900.
The Bormann fuze (fig. 42a), the quickest of the oldtimers to set, was used for many years by the U. S. Field Artillery in spherical sh.e.l.l and shrapnel. Its pewter case, which screwed into the sh.e.l.l, contained a time ring of powder composition (A). Over this ring the top of the fuze case was marked in seconds. To set the fuze, the gunner merely had to cut the case at the proper mark--at four for 4 seconds, three for 3 seconds, and so on--to expose the ring of powder to the powder blast of the gun. The ring burned until it reached the zero end and set off the fine powder in the center of the case; the powder flash then blew out a tin plate in the bottom of the fuze and ignited the sh.e.l.l charge. Its short burning time (about 6 seconds) made the Bormann fuze obsolete as field gun ranges increased. The main trouble with this fuze, however, was that it did not always ignite!
The percussion fuze was an extremely important development of the nineteenth century, particularly for the long-range rifles. The shock of impact caused this fuze to explode the sh.e.l.l at almost the instant of striking. Percussion fuzes were made in two general types: the front fuze, for the nose of an elongated projectile; and the base fuze, at the center of the projectile base. The base fuze was used with armor-piercing projectiles where it was desirable to have the sh.e.l.l penetrate the target for some distance before bursting. Both types were built on the same principles.
A Hotchkiss front percussion fuze (fig. 42e) had a bra.s.s case which screwed into the sh.e.l.l. Inside the case was a plunger (A) containing a priming charge of powder, topped with a cap of fulminate. A bra.s.s wire at the base of the plunger was a safety device to keep the cap away from a sharp point at the top of the fuze until the sh.e.l.l struck the target. When the gun was fired, the shock of discharge dropped a lead plug (B) from the base of the fuze into the projectile cavity, permitting the plunger to drop to the bottom of the fuze and rest there, held by the spread wire, while the sh.e.l.l was in flight. Upon impact, the plunger was thrown forward, the cap struck the point and ignited the priming charge, which in turn fired the bursting charge of the sh.e.l.l.
SCATTER PROJECTILES
When one of our progenitors wrathfully seized a handful of pebbles and flung them at the flock of birds in his garden, he discovered the principle of the scatter projectile. Perhaps its simplest application was in the stone mortar (fig. 43). For this weapon, round stones about the size of a man"s fist (and, by 1750, hand grenades) were dumped into a two-handled basket and let down into the bore. This primitive charge was used at close range against personnel in a fortification, where the effect of the descending projectiles would be uncommonly like a short but severe barrage of over-sized hailstones. There were 6,000 stones in the ammunition inventory for Castillo de San Marcos in 1707.
[Ill.u.s.tration: Figure 43--SPANISH 16-INCH PEDRERO (1788). This mortar fired baskets of stones.]
One of the earliest kinds of scatter projectiles was case shot, or canister, used at Constantinople in 1453. The name comes from its case, or can, usually metal, which was filled with sc.r.a.p, musket b.a.l.l.s, or slugs (fig. 41). Somewhat similar, but with larger iron b.a.l.l.s and no metal case, was grape shot, so-called from the grape-like appearance of the cl.u.s.tered b.a.l.l.s. A stand of grape in the 1700"s consisted of a wooden disk at the base of a short wooden rod that served as the core around which the b.a.l.l.s stood (fig. 41). The whole a.s.sembly was bagged in cloth and reinforced with a net of heavy cord.
In later years grape was made by bagging two or three tiers of b.a.l.l.s, each tier separated by an iron disk. Grape could disable men at almost 900 yards and was much used during the 1700"s. Eventually, it was almost replaced by case shot, which was more effective at shorter ranges (400 to 700 yards). Incidentally, there were 2,000 sacks of grape at the Castillo in 1740, more than any other type projectile.
Spherical case shot (fig. 41) was an attempt to carry the effectiveness of grape and canister beyond its previous range, by means of a bursting sh.e.l.l. It was the forerunner of the shrapnel used so much in World War I and was invented by Lt. Henry Shrapnel, of the British Army, in 1784. There had been previous attempts to produce a projectile of this kind, such as the German Zimmerman"s "hail shot" of 1573--case shot with a bursting charge and a primitive time fuze--but Shrapnel"s invention was the first air-bursting case shot which, in technical words, "imparted directional velocity" to the bullets it contained. Shrapnel"s new sh.e.l.l was first used against the French in 1808, but was not called by its inventor"s name until 1852.
INCENDIARIES AND CHEMICAL PROJECTILES
Incendiary missiles, such as buckets or barrels filled with a fiercely burning composition, had been used from earliest times, long before cannon. These crude incendiaries survived through the 1700"s as, for instance, the flaming cargoes of fire ships that were sent amidst the enemy fleet. But in the year 1672 there appeared an iron sh.e.l.l called a carca.s.s (fig. 41), filled with pitch and other materials that burned at intense heat for about 8 minutes. The flame escaped through vents, three to five in number, around the fuze hole of the sh.e.l.l. The carca.s.s was standard ammunition until smoothbores went out of use. The United States ordnance manual of 1861 lists carca.s.ses for 12-, 18-, 24-, 32-, and 42-pounder guns as well as 8-, 10-, and 13-inch mortars.
During the late 1500"s, the heating of iron cannon b.a.l.l.s to serve as incendiaries was suggested, but not for another 200 years was the idea successfully carried out. Hot shot was nothing but round shot, heated to a red glow over a grate or in a furnace. It was fired from cannon at such inflammable targets as wooden ships or powder magazines.
During the siege of Gibraltar in 1782, the English fired and destroyed a part of Spain"s fleet with hot shot; and in United States seacoast forts shot furnaces were standard equipment during the first half of the 1800"s. The little shot furnace at Castillo de San Marcos National Monument was built during the 1840"s; a giant furnace of 1862 still remains at Fort Jefferson National Monument. Few other examples are left.
Loading hot shot was not particularly dangerous. After the powder charge was in the gun with a dry wad in front of it, another wad of wet straw, or clay, was put into the barrel. When the cherry-red shot was rammed home, the wet wad prevented a premature explosion of the charge. According to the _Ordnance Manual_, the shot could cool in the gun without setting off the charge! Hot shot was superseded, about 1850, by Martin"s sh.e.l.l, filled with molten iron.
The smoke sh.e.l.l appeared in 1681, but was never extensively used.
Similarly, a form of gas projectile, called a "stink sh.e.l.l," was invented by a Confederate officer during the Civil War. Because of its "inhumanity," and probably because it was not thought valuable enough to offset its propaganda value to the enemy, it was not popular. These were the beginnings of the modern chemical sh.e.l.ls.
In connection with chemical warfare, it is of interest to review the Hussite siege of Castle Karlstein, near Prague, in the first quarter of the fifteenth century. The Hussites emplaced 46 small cannon, 5 large cannon, and 5 catapults. The big guns would shoot once or twice a day, and the little ones from six to a dozen rounds.
Marble pillars from Prague churches furnished the cannonb.a.l.l.s. Many projectiles for the catapults, however, were rotting carca.s.ses and other filth, hurled over the castle walls to cause disease and break the morale of the besieged. But the intrepid defenders neutralized these "chemical bursts" with lime and a.r.s.enic. After firing 10,930 cannonb.a.l.l.s, 932 stone fragments, 13 fire barrels, and 1,822 tons of filth, the Hussites gave up.
FIXED AMMUNITION
In early days, due partly to the roughly made b.a.l.l.s, wads were very important as a means of confining the powder and increasing its efficiency. Wads could be made of almost any suitable material at hand, but perhaps straw or hay ones were most common. The hay was first twisted into a 1-inch rope, then a length of the rope was folded together several times and finally rolled up into a short cylinder, a little larger than the bore. After the handier sabots came into use, however, wads were needed only to keep the ball from rolling out when the muzzle was down, or for hot shot firing.
Gunners early began to consolidate ammunition for easier and quicker loading. For instance, after the powder charge was placed in a bag, the next logical step was to attach the wad and the cannonball to it, so that loading could be made in one simple operation--pushing the single round into the bore (fig. 48). Toward that end, the sabot or "shoe" (fig. 41) took the place of the wad. The sabot was a wooden disk about the same diameter as the shot. It was secured to the ball with a pair of metal straps to make "semi-fixed" ammunition; then, if the neck of the powder bag were tied around the sabot, the result was one cartridge, containing powder, sabot, and ball, called "fixed"
ammunition. Fixed ammunition was usual for the lighter field pieces by the end of the 1700"s, while the bigger guns used "semi-fixed."
In transportation, cartridges were protected by cylinders and caps of strong paper. Sabots were sometimes made of paper, too, or of compressed wood chips, to eliminate the danger of a heavy, unbroken sabot falling amongst friendly troops. A big mortar sabot was a lethal projectile in itself!
ROCKETS
Today"s rocket projectiles are not exactly new inventions. About the time of artillery"s beginning, the military fireworker came into the business of providing pyrotechnic engines of war; later, his job included the spectacular fireworks that were set off in celebration of victory or peace.
Artillery manuals of very early date include chapters on the manufacture and use of fireworks. But in making war rockets there was no marked progress until the late eighteenth century. About 1780, the British Army in India watched the Orientals use them; and within the next quarter century William Congreve, who set about the task of producing a rocket that would carry an incendiary or explosive charge as far as 2 miles, had achieved such promising results that English boats fired rocket salvos against Boulogne in 1806, The British Field Rocket Brigade used rockets effectively at Leipsic in 1812--the first time they appeared in European land warfare. They were used again 2 years later at Waterloo. The warheads of such rockets were cast iron, filled with black powder and fitted with percussion fuzes. They were fired from trough-like launching stands, which were adjustable for elevation.
Rockets seem to have had a demoralizing effect upon untrained troops, and perhaps their use by the English against raw American levies at Bladenburg, in 1814, contributed to the rout of the United States forces and the capture of Washington. They also helped to inspire Francis Scott Key. Whether or not he understands the technical characteristics of the rocket, every schoolboy remembers the "rocket"s red glare" of the National Anthem, wherein Key recorded his eyewitness account of the bombardment of Fort McHenry. The U. S. Army in Mexico (1847) included a rocket battery, and, indeed, war rockets were an important part of artillery resources until the rapid progress of gunnery in the latter 1800"s made them obsolescent.
TOOLS
Gunner"s equipment was numerous. There were the tompion (a lid that fitted over the muzzle of the gun to keep wind and weather out of the bore) and the lead cover for the vent; water buckets for the sponges and pa.s.sing boxes for the powder; sc.r.a.pers and tools for "searching"
the bore to find dangerous cracks or holes; chocks for the wheels; blocks and rollers, lifting jacks, and gins for moving guns; and drills and augers for clearing the vent (figs. 17, 44). But among the most important tools for everyday firing were the following:
_The sponge_ was a wooden cylinder about a foot long, the same diameter as the shot, and covered with lambskin. Like all bore tools, it was mounted on a long staff; after being dampened with water, it was used for cleaning the bore of the piece after firing. Essentially, sponging made sure there were no sparks in the bore when the new charge was put in. Often the sponge was on the opposite end of the rammer, and sometimes, instead of being lambskin-covered, the sponge was a bristle brush.
_The wormer_ was a double screw, something like a pair of intertwined corkscrews, fixed to a long handle. Inserted in the gun bore and twisted, it seized and drew out wads or the remains of cartridge bags stuck in the gun after firing. Worm screws were sometimes mounted in the head of the sponge, so that the piece could be sponged and wormed at the same time.
_The ladle_ was the most important of all the gunner"s tools in the early years, since it was not only the measure for the powder but the only way to dump the powder in the bore at the proper place. It was generally made of copper, the same gauge as the windage of the gun; that is, the copper was just thick enough to fit between ball and bore.
Essentially, the ladle is merely a scoop, a metal cylinder secured to a wooden disk on a long staff. But before the introduction of the powder cartridge, cutting a ladle to the right size was one of the most important accomplishments a gunner had to learn. Collado, that Spanish mathematician of the sixteenth century, used the culverin ladle as the master pattern (fig. 45). It was 4-1/2 calibers long and would carry exactly the weight of the ball in powder. Ladles for lesser guns could be proportioned (that is, shortened) from the master pattern.