Jack Norman, age 12, of Albuquerque, N.M., for his question:

WHEN WAS THE CANNON INVENTED?

Cannon is a general term for large military weapons supported on carriages or fixed mounts, as opposed to small arms. The invention of the cannon is generally credited to a German monk named Berthold Schwarz who came up with the idea in the early 14th century.

The first cannon used gunpowder charges to fire stones or metal balls. Early cannons were smoothbore metal tubes loaded from the muzzle and aimed and elevated manually. Recoil was absorbed by allowing the carriage to run backward.

In modern military usage the term cannon is synonymous with artillery. The modern cannon, loaded through the breech (at the rear of the bore), consists of a forged steel tube, rifled (that is, having a grooved bore) to give the projectile a spin in flight and enclosed for strength in a steel jacket. The carriage is equipped with mechanisms to absorb the force of recoil on firing and return the cannon to firing position.

In the modern cannon, elevating and traversing mechanisms provide for accurate aiming by hand, by electric power or by a completely automatic system that locates and tracks targets byradar.