Book 14 · 备高临 · Chapter 44
禽子再拜再拜曰：“敢问适人积土为高，以临吾城，薪土俱上，以为羊黔，蒙橹俱前，遂属之城，兵弩俱上，为之柰何？”
Master Qin bowed twice and twice again, and said: "May I venture to ask: the enemy heaps up earth to make a height, in order to overlook our city; faggots and earth are carried up together to form a 'ram-mound' (yangqian); shielded by mantlets they all advance together, until it adjoins the city wall, and weapons and crossbows are all brought up. What is to be done about this?"
子墨子曰：“子问羊黔之守邪？羊黔者将之拙者也，足以劳卒，不足以害城。守为台城，以临羊黔，左右出巨，各二十尺，行城三十尺，强弩射之，技机藉之，奇器口口之，然则羊黔之攻败矣。
Master Mozi said: "Are you asking about the defense against the ram-mound? The ram-mound is the device of a clumsy commander. It is enough to wear out the troops, but not enough to harm the city. The defender builds a terrace-wall (taicheng) to overlook the ram-mound, with projecting beams (ju) extending left and right, each twenty feet long, and a parapet-walk thirty feet [high?]. Shoot at them with strong crossbows, press them with mechanical engines, and [ . . . ] them with ingenious devices; then the attack by the ram-mound will be defeated.
备临以连弩之车材大方一方一尺，长称城之薄厚。两轴三轮，轮居筐中，重下上筐。左右旁二植，左右有衡植，衡植左右皆圜内，内径四寸。左右縳弩皆于植，以弦钩弦，至于大弦。弩臂前后与筐齐，筐高八尺，弩轴去下筐三尺五寸。连弩机郭同铜，一石三十钧。引弦鹿长奴。筐大三围半，左右有钩距，方三寸，轮厚尺二寸，钩距臂博尺四寸，厚七寸，长六尺。横臂齐筐外，蚤尺五寸，有距，博六寸，厚三寸，长如筐，有仪，有诎胜，可上下。为武重一石以材大围五寸。矢长十尺，以绳系箭矢端，如如戈射，以磿鹿卷收。矢高弩臂三尺，用弩无数，出人六十枚，用小矢无留。十人主此车。遂具寇，为高楼以射道，城上以荅、罗，矢。
To defend against an elevated attack, use the carriage of the linked (repeating) crossbow. Its timber, large and square, is one square foot in cross-section, and its length is to match the thickness of the wall. It has two axles and three wheels, the wheels sitting within the frame (kuang), the lower frame being heavier than the upper. On the left and right sides are two uprights, and left and right there are crossbars and uprights; the crossbars and uprights on left and right all have round sockets, the sockets four inches in inner diameter. The crossbows are bound left and right onto the uprights; by means of a string-hook the [firing] string catches the great [bow]string. The crossbow-arm (nubi), front and back, is flush with the frame; the frame is eight feet high, and the crossbow axle is three feet five inches above the lower frame. The mechanism and casing (jiguo) of the repeating crossbow are alike of bronze, [weighing] one stone and thirty jun. The string is drawn back with a windlass (luchang) [worked by] a slave. The frame is three and a half spans in girth. Left and right there are hook-distances (gouju), three inches square; the wheels are one foot two inches thick; the hook-distance arm is one foot four inches broad, seven inches thick, and six feet long. The cross-arm is flush with the outside of the frame, and is one foot five inches at the claw (zao); it has a distance-piece (ju), six inches broad, three inches thick, and as long as the frame; it has a gnomon (yi) and a folding/raising device (qusheng), so that it can be moved up and down. The 'weight' (wu) weighs one stone, made of timber five inches in girth. The arrows (bolts) are ten feet long; a cord is fastened to the butt-end of the arrow, [shot] as with a halberd-shot (geshe), and reeled back in with a windlass. The arrow stands three feet above the crossbow-arm. The crossbows are used without count [of shots]; sixty bolts are sent out and drawn back, and small arrows are used without retaining [them]. Ten men have charge of this carriage. When at length the enemy is fully equipped, build high towers to shoot down the approach-roads; on the walls use ta-shields and ba-nets, and arrows."