Battering Ram
2 of the 7 encyclopedias on this shelf carry an entry for Battering Ram. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
a device for hammering down the walls of cities. Before the invention of gunpowder, the chief defense of a city consisted in a high wall, with entrances defended by massive gates. The battering ram employed by the ancients for hammering down these walls was of two sorts. The chief feature of the first was a huge beam swung by cables in a frame. The end of the beam was shod frequently with an iron head, and the frame in which it swung was provided with a roof to protect the operators from a shower of stones and javelins from the top of the wall above. A number of men applying their strength to the beam caused it to swing to and fro in such a way that one end struck the wall with tremendous force. The other sort was operated on rollers. The force of the battering ram depended, of course, on the weight of the beam and the force with which it was propelled. Rams, employed by the Romans at the siege of Carthage, were so large that a hundred men were required for their operation. A Roman writer describes one that must have weighed over twenty tons. Those in charge are said to have made a study of striking the wall at the right moment, so that the force of the blow might be added to the natural vibrations of the wall, just as a boy learns to push a swing. The frame of a ram was moved to and fro on rollers. 2026 Editor's Note: The siege engine faded with the cannon, but the battering ram lives on in miniature: the handheld steel 'ram' that police use to break down doors in raids works on the same brute principle the ancients knew, as does the heavier 'ram' that breaches locked gates. (Ed: BR 2026-07-01)
Collier's New Encyclopedia (1921)
an ancient military contrivance used for battering down walls. It existed among the Assyrians. In its most perfect form among the BATTERING RAM Romans it consisted of a pole or beam of wood, sometimes as much as 80, 100, or even 120 feet in length. It was suspended by its extremities from a single point, or from two points in another beam above, which lay horizontally across two posts. When at rest it was level, like the beam above it. When put in action against a wall, it was swung horizontally by men who succeeded each other in constant relays, the blow which it gave to the masonry at each vibration being rendered all the more effective that one end of it was armed with iron. This, being generally formed like a ram's head, originated the name aries (ram), by which it was known among the Romans, and battering-ram, by which it was afterward known. A roof or shed covered it to protect the soldiers who worked it, from hostile missiles, and to facilitate locomotion it was often placed on wheels.