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 shell called
a carcass (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 shell. The
carcass was standard ammunition until smoothbores went out of use. The
United States ordnance manual of 1861 lists carcasses 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 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 Hot shot was superseded, about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.