A full or semi-detached scarp-wall will be breached when the battery is on the glacis by making vertical cuts at the ends, and a horizontal cut at about one third or one fourth its height from the bottom, and then firing shells into the part to be brought down, continuing the fire until the large masses of masonry are broken up, and the slope is made gentle and smooth enough to admit of easy ascent. A detached scarp-wall will be breached by a glacis battery, or any scarp-wall by a distant battery, by continued battering, which will not only knock down the wall, but also break up the fragments and make a practicable ramp. =93.= =The Capture and Crowning of the Breach.=--The decision as to whether the breach shall be captured and crowned by _assault_ or by _sap_ will be governed by considerations similar to those which determined the character of the attack upon the covered way. The difficulties and dangers of the assault are perhaps greater than in that case. The =assault=, if undertaken, will be carried out in a similar manner, previous preparations having been made by making a practicable breach at least 25 to 30 yards wide, a practicable descent into the ditch of equal width, and a covered place of assembly for the working party and a depot of trench materials in immediate proximity to the breach. The artillery defence of the ditch, whether from caponières, flank embrasures or casemates, or from adjacent works, must of course be silenced before crossing the ditch either by assault or by regular approach. This is accomplished by counter-batteries on the glacis, by heavy field guns located in temporary batteries in the trenches, by mines, or by overhead or indirect fire from the distant batteries, or from light mortars in the advanced trenches, as may be necessary. If the interior arrangement of the work is known by the besieger the assault maybe made by night; but if it is unknown, the confusion resulting from a night attack will be so great as to render its success almost hopeless, and the assault will have to be delivered by day. The assaulting columns will be made up of an advanced line of skirmishers (selected men, good shots, and generally volunteers), followed by a working party of sappers to clear away obstacles, these closely followed by the columns of assault; while the supports and reserves move forward in the trenches to join in the assault as circumstances require. The troops who first gain the crest establish themselves there and hold the breach until those coming after them pass and engage the garrison, while some detachments strive to capture and open one gate or more to admit the reserves. The assaulting force should be equal at least to once and a half or twice the garrison, and simultaneous attacks should be made upon other breaches or accessible parts of the work to divide the attention of the defence.