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scarps, to make up for the want or deficiency offlank fire from the parapet, so any expedient bywhich a ditch, so protected, can be crossed atthe top, is deserving of favourable considerationand adoption. But these expedients can onlybe resorted to when the ground in front of thework is clear from local impediments or arti-ficial obstacles, so that several carriage-bridgesmay be run up in line. If the ground be soft,such machines would occasion but little noisein their movement; and by nailing leather onthe wheels, using leather washers, and otherprecautions, noise might be almost entirely pre-vented. Expedients of this nature may un-doubtedly be of service, either in the assault ofworks; or to cross any ditches, canals, or otherimpediments, by which the approaches to the■works may be covered : and although attemptsby such means may be difficult, yet thelosses attending them, will not, in general, beso great, as to fill up ditches, inundations, &c.by materials carried up by hand, under a heavyand protracted fire.

These latter constructions and expedientsWould appear, more properly, to belong to aformer article (on Carriage-bridges); but onaccount of their connection with the operationstreated of in this section, I have deviated alittle from strict arrangement in these parts.

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