ed the defects of the
chambered pieces. A 60-pounder reinforced cannon fired a convenient
55-pound ball, was easy to move, load, and clean, and held up well
under any kind of service. It cooled quickly. Either cannon powder or
fine powder (up to two-thirds the ball's weight) could be used in it.
Reinforced cannon were an important factor in any enterprise, as King
Philip's famed "Twelve Apostles" proved during the Flanders wars.

_Fortification of sixteenth and seventeenth century guns_

------------------------+-------------------------+---------------------
| Thickness of bore wall |
| in 8ths of the caliber |
Spanish Guns +-------+---------+-------+ 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