Part 7 (1/2)
HOWITZERS
The howitzer was invented by the Dutch in the seventeenth century to throw larger projectiles (usually bombs) than could the field pieces, in a high trajectory similar to the mortar, but from a lighter and more mobile weapon. The wide-purpose efficiency of the howitzer was appreciated almost at once, and it was soon adopted by all European armies. The weapon owed its mobility to a rugged, two-wheeled carriage like a field carriage, but with a relatively short trail that permitted the wide arc of elevation needed for this weapon.
[Ill.u.s.tration: Figure 34--SPANISH 6-INCH HOWITZER (1759-88). This bronze piece was founded during the reign of Charles III and bears his s.h.i.+eld. a--Dolphin, or handle, b--Bore, c--Powder chamber.]
English howitzers of the 1750's were of three calibers: 5.8-, 8-, and 10-inch, but the 10-incher was so heavy (some 50 inches long and over 3,500 pounds) that it was quickly discarded. Muller deplored the superfluous weight of these pieces and developed 6-, 8-, 10, and 13-inch howitzers in which, by a more calculated distribution of the metal, he achieved much lighter weapons. Muller's howitzers survived in the early 6- to 10-inch pieces of United States artillery and one fine little 24-pounder of the late eighteenth century happens to be among the armament of Castillo de San Marcos, along with some early nineteenth century howitzers. The British, incidentally, were the first to bring this type gun to Florida. None appeared on the Castillo inventory until the 1760's.
[Ill.u.s.tration: Figure 35--ENGLISH 8-INCH ”HOWITZ” CARRIAGE (1756). The short trail enabled greater lat.i.tude in elevating the howitzer.]
In addition to the very light and therefore easily portable mountain howitzer used for Indian warfare, United States artillery of 1850 included 12-, 24-, and 32-pounder field, 24-pounder and 8-inch siege and garrison, and the 10-inch seacoast howitzer. The Navy had a 12-pounder heavy and a 24-pounder, to which were added the 12- and 24-pounder Dahlgren rifled howitzers of the Civil War period. Such guns were often used in landing operations. The following table gives some typical ranges:
_Ranges of U. S. Howitzers in the 1860's_
Caliber Elevation Range in yards
10-inch seacoast 5 1,650 8-inch siege 1230' 2,280 24-pounder naval 5 1,270 12-pounder heavy naval 5 1,085 20-pounder Dahlgren rifled 5 1,960 12-pounder Dahlgren rifled 5 1,770
[Ill.u.s.tration: Figure 36--ENGLISH MORTAR ON ELEVATING BED (1740).]
From earliest times the usefulness of the mortar as an arm of the artillery has been clearly recognized. Up until the 1800's the weapon was usually made of bronze, and many mortars had a fixed elevation of 45, which in the sixteenth century was thought to be the proper elevation for maximum range of any cannon. In the 1750's Muller complained of the stupidity of English artillerists in continuing to use fixed-elevation mortars, and the Spanish made a _mortero de plancha_, or ”plate” mortar (fig. 37), as late as 1788. Range for such a fixed-elevation weapon was varied by using more or less powder, as the case required. But the most useful mortar, of course, had trunnions and adjustable elevation by means of quoins.
[Ill.u.s.tration: Figure 37--SPANISH 5-INCH BRONZE MORTAR (1788).]
The mortar was mounted on a ”bed”--a pair of wooden cheeks held together by transoms. Since a bed had no wheels, the piece was transported on a mortar wagon or sling cart. In the battery, the mortar was generally bedded upon a level wooden platform; aboard s.h.i.+p, it was a revolving platform, so that the piece could be quickly aimed right or left. The mortar's weight, plus the high angle of elevation, kept it pretty well in place when it was fired, although English artillerists took the additional precaution of las.h.i.+ng it down.
The mortar did not use a wad, because a wad prevented the fuze of the sh.e.l.l from igniting. To the layman, it may seem strange that the sh.e.l.l was never loaded with the fuze toward the powder charge of the gun.
But the fuze was always toward the muzzle and away from the blast, a practice which dated from the early days when mortars were discharged by ”double firing”: the gunner lit the fuze of the sh.e.l.l with one hand and the priming of the mortar with the other. Not until the late 1600's did the method of letting the powder blast ignite the fuze become general. It was a change that greatly simplified the use of the arm and, no doubt, caused the mortarman to heave a sigh of relief.
[Ill.u.s.tration: Figure 38--SPANISH 10-INCH BRONZE MORTAR (1759-88).
a--Dolphin, or handle, b--Bore, c--Powder chamber.]
Most mortars were equipped with dolphins, either singly or in pairs, which were used for lifting the weapon onto its bed. Often there was a little bracketed cup--a priming pan--under the vent, a handy gadget that saved spilling a lot of powder at the almost vertical breech. As with other bronze cannon, mortars were embellished with s.h.i.+elds, scrolls, names, and other decoration.
About 1750, the French mortar had a bore length 1-1/2 diameters of the sh.e.l.l; in England, the bore was 2 diameters for the smaller calibers and 3 for the 10- and 13-inchers. The extra length added a great deal of weight to the English mortars: the 13-inch weighed 25 hundredweight, while the French equivalent weighed only about half that much. Muller complained that mortar designers slavishly copied what they saw in other guns. For instance, he said, the reinforce was unnecessary; it ”... overloads the Mortar with a heap of useless metal, and that in a place where the least strength is required, yet as if this unnecessary metal was not sufficient, they add a great projection at the mouth, which serves to no other purpose than to make the Mortar top-heavy. The mouldings are likewise jumbled together, without any taste or method, tho' they are taken from architecture.”
Field mortars in use during Muller's time included 4.6-, 5.8-, 8-, 10-, and 13-inch ”land” mortars and 10- and 13-inch ”sea” mortars.
Muller, of course, redesigned them.
[Ill.u.s.tration: Figure 39--COEHORN MORTAR. The British General Oglethorpe used 20 coehorns in his 1740 bombardment of St. Augustine.
These small mortars were also used extensively during the War Between the States.]
The small mortars called coehorns (fig. 39) were invented by the famed Dutch military engineer, Baron van Menno Coehoorn, and used by him in 1673 to the great discomfit of French garrisons. Oglethorpe had many of them in his 1740 bombardment of St. Augustine when the Spanish, trying to translate coehorn into their own tongue, called them _cuernos de vaca_--”cow horns.” They continued in use through the U.
S. Civil War, and some of them may still be seen in the battlefield parks today.
Bombs and carca.s.ses were usual for mortar firing, but stone projectiles remained in use as late as 1800 for the pedrero cla.s.s (fig. 43). Mortar projectiles were quite formidable; even in the sixteenth century missiles weighing 100 or more pounds were not uncommon, and the 13-inch mortar of 1860 fired a 200-pound sh.e.l.l. The larger projectiles had to be whipped up to the muzzle with block and tackle.
[Ill.u.s.tration: Figure 40--THE ”DICTATOR.” This huge 13-inch mortar was used by the Federal artillery in the bombardment of Petersburg, Va., 1864-65.]