Part 7

During the late 1500's, the heating of iron cannon balls 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 Hot shot was superseded, about 1850, by Martin's shell, filled with molten iron.

The smoke shell appeared in 1681, but was never extensively used. Similarly, a form of gas projectile, called a "stink shell," 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 shells.

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 cannonballs. Many projectiles for the catapults, however, were rotting carcasses 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 arsenic. After firing 10,930 cannonballs, 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 balls, 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 passing boxes for the powder; scrapers 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.

[Illustration: Figure 44--EIGHTEENTH CENTURY GUNNER'S EQUIPMENT. (Not to scale.)]

The ladle full of powder was pushed home in the bore. Turning the handle dumped the charge, which then had to be packed with the rammer. As powder charges were lessened in later years, the ladle was shortened; by 1750, it was only three shot diameters long. With cartridges, the ladle was no longer needed for loading the gun, but it was still handy for withdrawing the round.

_The rammer_ was a wooden cylinder about the same diameter and length as the shot. It pushed home the powder charge, the wad, and the shot. As a precaution against faulty or double loading, marks on the rammer handle showed the loaders when the different parts of the charge were properly seated.

_The gunner's pick or priming wire_ was a sharp pointed tool resembling a common ice pick blade. It was used to clear the vent of the gun and to pierce the powder bag so that flame from the primer could ignite the charge.

[Illustration: Figure 45--SIXTEENTH CENTURY PATTERN FOR GUNNER'S LADLE.]

_Handspikes_ were big pinch bars to manhandle cannon. They were used to move the carriage and to lift the breech of the gun so that the elevating quoin or screw might be adjusted. They were of different types (figs. 33a, 44), but were essentially 6-foot-long wooden poles, shod with iron. Some of them, like the Marsilly handspike (fig. 11), had rollers at the toe so that the wheelless rear of the carriage could be lifted with the handspike and rolled with comparative ease.

_The gunner's quadrant_ (fig. 46), invented by Tartaglia about 1545, was an aiming device so basic that its principle is still in use today. The instrument looked like a carpenter's square, with a quarter-circle connecting the two arms. From the angle of the square dangled a plumb bob. The gunner laid the long arm of the quadrant in the bore of the gun, and the line of the bob against the graduated quarter-circle showed the gun's angle of elevation.

The addition of the quadrant to the art of artillery opened a whole new field for the mathematicians, who set about compiling long, complicated, and jealously guarded tables for the gunner's guidance. But the theory was simple: since a cannon at 45° elevation would fire _ten_ times farther than it would when the barrel was level (at zero° elevation), the quadrant should be marked into _ten_ equal parts; the range of the gun would therefore increase by _one-tenth_ each time the gun was elevated to the next mark on the quadrant. In other words, the gunner could get the range he wanted simply by raising his piece to the proper mark on the instrument.

[Illustration: Figure 46--SEVENTEENTH CENTURY GUNNER'S QUADRANT. The long end of the quadrant was laid in the bore of the cannon. The plumb bob indicated the degree of elevation on the scale.]

Collado explained how it worked in the 1590's. "We experimented with a culverin that fired a 20-pound iron ball. At point-blank the first shot ranged 200 paces. At 45-degree elevation it shot ten times farther, or 2,000 paces.... If the point-blank range is 200 paces, then elevating to the _first_ position, or a tenth part of the quadrant, will gain 180 paces more, and advancing another point will gain so much again. It is the same with the other points up to the elevation of 45 degrees; each one gains the same 180 paces." Collado admitted that results were not always consistent with theory, but it was many years before the physicists understood the effect of air resistance on the trajectory of the projectile.

_Sights_ on cannon were usually conspicuous by their absence in the early days. A dispart sight (an instrument similar to the modern infantry rifle sight), which compensated for the difference in diameter between the breech and the muzzle, was used in 1610, but the average artilleryman still aimed by sighting over the barrel. The Spanish gunner, however, performed an operation that put the bore parallel to the gunner's line of sight, and called it "killing the _vivo_" (_matar el vivo_). How _vivo_ affected aiming is easily seen: with its bore level, a 4-pounder falconet ranged 250 paces. But when the _top of the gun_ was level, the bore was slightly elevated and the range almost doubled to 440 paces.

To "kill the _vivo_," you first had to find it. The gunner stuck his pick into the vent down to the bottom of the bore and marked the pick to show the depth. Next he took the pick to the muzzle, stood it up in the bore, and marked the height of the muzzle. The difference between the two marks, with an adjustment for the base ring (which was higher than the vent), was the _vivo_. A little wedge of the proper size, placed under the breech, would then eliminate the troublesome _vivo_.

During the first half of the 1700's Spanish cannon of the "new invention" were made with a notch at the top of the base ring and a sighting button on the muzzle, and these features were also adopted by the French. But they soon went out of use. There was some argument, as late as the 1750's, about the desirability of casting the muzzle the same size as the base ring, so that the sighting line over the gun would always be parallel to the bore; but, since the gun usually had to be aimed higher than the objective, gunners claimed that a fat muzzle hid their target!

[Illustration: Figure 47--SEVENTEENTH CENTURY GUNNER'S LEVEL. This tool was useful in many ways, but principally for finding the line of sight on the barrel of the gun.]

Common practice for sighting, as late as the 1850's, was to find the center line at the top of the piece, mark it with chalk or filed notches, and use it as a sighting line. To find this center line, the gunner laid his level (fig. 47) first on the base ring, then on the muzzle. When the instrument was level atop these rings, the plumb bob was theoretically over the center line of the cannon. But guns were crudely made, and such a line on the outside of the piece was not likely to coincide exactly with the center line of the bore, so there was still ample opportunity for the gunner to exercise his "art." Nonetheless the marked lines did help, for the gunner learned by experiment how to compensate for errors.

Fixed rear sights came into use early in the 1800's, and tangent sights (graduated rear sights) were in use during the War Between the States. The trunnion sight, a graduated sight attached to the trunnion, could be used when the muzzle had to be elevated so high that it blocked the gunner's view of the target.

Naval gunnery officers would occasionally order all their guns trained at the same angle and elevated to the same degree. The gunner might not even see his target. While with the crude traversing mechanism of the early 1800's the gunners may not have laid their pieces too accurately, at least it was a step toward the indirect firing technique of later years which was to take full advantage of the longer ranges possible with modern cannon. Use of tangent and trunnion sights brought gunnery further into the realm of mathematical science; the telescopic sight came about the middle of the nineteenth century; gunners were developing into technicians whose job was merely to load the piece and set the instruments as instructed by officers in fire control posts some distance away from the gun.

THE PRACTICE OF GUNNERY

The old-time gunner was not only an artist, vastly superior to the average soldier, but, when circumstances permitted, he performed his wizardry with all due ceremony. Diego Ufano, Governor of Antwerp, watched a gun crew at work about 1500:

"The piece having arrived at the battery and being provided with all needful materials, the gunner and his assistants take their places, and the drummer is to beat a roll. The gunner cleans the piece carefully with a dry rammer, and in pulling out the said rammer gives a dab or two to the mouth of the piece to remove any dirt adhering." (At this point it was customary to make the sign of the cross and invoke the intercession of St. Barbara.)

"Then he has his assistant hold the sack, valise, or box of powder, and filling the charger level full, gives a slight movement with the other hand to remove any surplus, and then puts it into the gun as far as it will go. Which being done, he turns the charger so that the powder fills the breech and does not trail out on the ground, for when it takes fire there it is very annoying to the gunner." (And probably to the gentleman holding the sack.)

"After this he will take the rammer, and, putting it into the gun, gives two or three good punches to ram the powder well in to the chamber, while his assistant holds a finger in the vent so that the powder does not leap forth. This done, he takes a second charge of powder and deposits it like the first; then puts in a wad of straw or rags which will be well packed to gather up all the loose powder. This having been well seated with strong blows of the rammer, he sponges out the piece.

"Then the ball, well cleaned by his assistant, since there is danger to the gunner in balls to which sand or dirt adhere, is placed in the piece without forcing it till it touches gently on the wad, the gunner being careful not to hold himself in front of the gun, for it is silly to run danger without reason. Finally he will put in one more wad, and at another roll of drums the piece is ready to fire."

Maximum firing rate for field pieces in the early days was eight rounds an hour. It increased later to 100 rounds a day for light guns and 30 for heavy pieces. (Modern non-automatic guns can fire 15 rounds per minute.) After about 40 rounds the gun became so hot it was unsafe to load, whereupon it was "refreshed" with an hour's rest.

[Illustration: Figure 48--LOADING A CANNON. Muzzle-loading smoothbore cannon were used for almost 700 years.]

Approved aiming procedure was to make the first shot surely short, in order to have a measurement of the error. The second shot would be at greater elevation, but also cautiously short. After the third round, the gunner could hope to get hits. Beginners were cautioned against the desire to hit the target at the first shot, for, said a celebrated artillerist, "... you will get overs and cannot estimate how much over."

As gunners gradually became professional soldiers, gun drills took on a more military aspect, as these seventeenth century commands show:

1. Put back your piece. 2. Order your piece to load. 3. Search your piece. 4. Sponge your piece. 5. Fill your ladle. 6. Put in your powder. 7. Empty your ladle. 8. Put up your powder. 9. Thrust home your wad. 10. Regard your shot. 11. Put home your shot gently. 12. Thrust home your wad with three strokes. 13. Gauge your piece.

Gunners had no trouble finding work, as is singularly illustrated by the case of Andrew Ransom, a stray Englishman captured near St. Augustine in the late 1600's. He was condemned to death. The executional device failed, however, and the padres in attendance took it as an act of God and led Ransom to sanctuary at the friary. Meanwhile, the Spanish governor learned this man was an artillerist and a maker of "artificial fires." The governor offered to "protect" him if he would live at the Castillo and put his talents to use. Ransom did.

[Illustration: Figure 49--A SIEGE BOMBARD OF THE 1500's.]

By 1800, although guns could be served with as few as three men, efficient drill usually called for a much larger force. The smallest crew listed in the United States Navy manual of 1866 was seven: first and second gun captains, two loaders, two spongers, and a "powder monkey" (powder boy). An 11-inch pivot-gun on its revolving carriage was served by 24 crewmen and a powderman. In the field, transportation for a 24-pounder siege gun took 10 horses and 5 drivers.

Twelve rounds an hour was good practice for heavy guns during the Civil War period, although the figure could be upped to 20 rounds. By this date, of course, although the principles of muzzle loading had not changed, actual loading of the gun was greatly simplified by using fixed and semi-fixed ammunition. Loading technique varied with the gun, but the following summary of drill from the United States _Heavy Ordnance Manual_ of 1861 gives a fair idea of how the crew handled a siege gun:

In the first place, consider that the equipment is all in its proper place. The gun is on a two-wheeled siege carriage, and is "in battery," or pushed forward on the platform until the muzzle is in the earthwork embrasure. On each side of the gun are three handspikes, leaning against the parapet. On the right of the gun a sponge and a rammer are laid on a prop, about 6 feet away from the carriage. Near the left muzzle of the gun is a stack of cannonballs, wads, and a "passbox" or powder bucket. Hanging from the cascabel are two pouches: the tube-pouch containing friction "tubes" (primers for the vent) and the lanyard; and the gunner's pouch with the gunner's level, breech-sight, pick, gimlet, vent-punch, chalk, and fingerstall (a leather cover for the gunner's second left finger when the gun gets hot). Under the wheels are two chocks; the vent-cover is on the vent, a tompion in the muzzle; a broom leans against the parapet beyond the stack of cannonballs. A wormer, ladle, and wrench were also part of the battery equipment.

The crew consisted of a gunner and six cannoneers. At the command _Take implements_ the gunner stepped to the cascabel and handed the vent-cover to No. 2; the tube-pouch he gave to No. 3; he put on his fingerstall, leveled the gun with the elevating screw, applied his level to base ring and muzzle to find the highest points of the barrel, and marked these points with chalk for a line of sight. His six crewmen took their positions about a yard apart, three men on each side of the gun, with handspikes ready.