Fortification of sixteenth and seventeenth century guns
| Spanish Guns | Thickness of bore wall in 8ths of the caliber | English guns | ||
|---|---|---|---|---|
| Vent | Trunnions | Chase | ||
| Light cannon; bell-chambered cannon | 6 | 4-1/2 | 2-1/2 | Bastard cannon. |
| Demicannon | 6 | 5 | 3 | |
| Common cannon; common siege cannon | 7 | 5 | 3-1/2 | |
| Light culverin; common battering cannon | 7 | 5 | 3 | Bastard culverin; legitimate cannon. |
| Common culverin; reinforced cannon | 8 | 5-1/2 | 3-1/2 | Legitimate culverin; double-fortified cannon. |
| Legitimate culverin | 9 | 6-1/2 | 4 | Double-fortified culverin. |
| Cast-iron cannon | 10 | 8 | 5 | |
| Pasavolante | 11-1/2 | 8-1/2 | 5-1/2 | |
While there was little real progress in mobility until the days of Gustavus Adolphus, the wheeled artillery carriage seems to have been invented by the Venetians in the fifteenth century. The essential parts of the design were early established: two large, heavy cheeks or side pieces set on an axle and connected by transoms. The gun was cradled between the cheeks, the rear ends of which formed a "trail" for stabilizing and maneuvering the piece.
Wheels were perhaps the greatest problem. As early as the 1500's carpenters and wheelwrights were debating whether dished wheels were best. "They say," reported Collado, "that the [dished] wheel will never twist when the artillery is on the march. Others say that a wheel with spokes angled beyond the cask cannot carry the weight of the piece without twisting the spoke, so the wheel does not last long. I am of the same opinion, for it is certain that a perpendicular wheel will suffer more weight than the other. The defect of twisting under the pieces when on the march will be remedied by making the cart a little wider than usual." However, advocates of the dished wheel finally won.
SMOOTHBORES OF THE LATER PERIOD
From the guns of Queen Elizabeth's time came the 6-, 9-, 12-, 18-, 24-, 32-, and 42-pounder classifications adopted by Cromwell's government and used by the English well through the eighteenth century. On the Continent, during much of this period, the French were acknowledged leaders. Louis XIV (1643-1715) brought several foreign guns into his ordnance, standardizing a set of calibers (4-, 8-, 12-, 16-, 24-, 32-, and 48-pounders) quite different from Henry II's in the previous century.
The cannon of the late 1600's was an ornate masterpiece of the foundryman's art, covered with escutcheons, floral relief, scrolls, and heavy moldings, the most characteristic of which was perhaps the banded muzzle (figs. [23b-c], [25], [26a-b]), that bulbous bit of ornamentation which had been popular with designers since the days of the bombards. The flared or bell-shaped muzzle (figs. [23a], [26c], [27]), did not supplant the banded muzzle until the eighteenth century, and, while the flaring bell is a usual characteristic of ordnance founded between 1730 and 1830, some banded-muzzle guns were made as late as 1746 (fig. [26a]).
By 1750; however, design and construction were fairly well standardized in a gun of much cleaner line than the cannon of 1650. Although as yet there had been no sharp break with the older traditions, the shape and weight of the cannon in relation to the stresses of firing were becoming increasingly important to the men who did the designing.
Conditions in eighteenth century England were more or less typical: in the 1730's Surveyor-General Armstrong's formulae for gun design were hardly more than continuations of the earlier ways. His guns were about 20 calibers long, with these outside proportions:
| 1st reinforce | = 2/7 of the gun's length. |
| 2d reinforce | = 1/7 plus 1 caliber. |
| chase | = 4/7 less 1 caliber. |