ATTACK AND DEFENCE. 169 



placed that it can be enfiladed from the fortress, then its flank is covered by 

 an epaulenient, or else broken and mounted with guns. If the battery is not 

 in the parallel, it must be united with it by ditches of communication (N) ; 

 if in it, then a ditch of communication is carried round in the rear (N, fig, 

 32), All pieces stand in the batteries upon wooden platforms. These plat- 

 forms {fig- 29, side view, right ; upper view, left) consist of three sleepers, 

 hhh, upon which the platform planks, ppp, are bolted down ; a sleeper, u^ 

 being substituted for the last, to check the recoil. For the safe preservation 

 of the ammunition, bomb-proof powder-magazines are constructed within 

 batteries (D, fig. 30), large enough to contain the supply requisite for one 

 day's service. In mortar and howitzer batteries, a separate place, E, is 

 excavated for the shells and howitzes. All these magazines are connected 

 by galleries {qk) with the interior of the battery. 



Before the actual construction of a battery can be commenced, its location 

 in the parallel must be determined, its position above or below the horizon, 

 the direction of its axis of fire, the number and kind of its pieces, and the 

 circumstances under which it is to be built, as well as the materials which 

 are to be employed. The earth is obtained usually from ditches practised 

 in front and rear of the battery ; as, however, most of the slopes require to 

 be steeper than the natural slope of the earth, a revetment must be given to 

 them. For this purpose, fascines and gabions are emplo3'^ed. Fig. 28 gives 

 the interior view of a horizontal counter-battery, which is revetted to the 

 level of the embrasure soles with fascines. These fascines are fastened 

 against the parapet, as shown in the section (figs. 26, 27), by means of 

 anchors from two to five feet long, and anchor-stakes, which must extend 

 so far into the parapet as to be within the natural slope of the earth. * The 

 right half of fig. 28 shows the fascine revetment continued to the superior 

 slope of the parapet, while on the left this revetment is effected by means 

 of gabions, which must also be anchored, as shown in fig. 19. The sole of 

 embrasures is never revetted, but their sides (cheeks) may be revetted either 

 with fascines {fig. 26) or hurdles {fig- 27). We will now describe some 

 particular kinds of battery, and give the details of their construction. 



To construct a horizontal breach or counter-battery under the grape and 

 musketry fire of the enemy, the method of procedure is as follows : Let the 

 battery {pi. 50, fig. 42, ground plan, fig. 43, section) be destined for four 

 12-pounders : the front, GH, according to the line of direction, RL, being 

 oblique to, and 120 feet distant from, the second parallel. From the twa 

 points, 71, in the parallel, W, the full saps, n G and n H, are carried in the 

 directions G and H ; the sappers then proceed parallel with R L to pp, 

 inclosing a space large enough to yield earth for the battery ; then the sap- 

 pers approach each other from the two opposite points, until the sap, pp, is 

 completed ; and at GH a flying sap is thrown up to determine the fire line. 

 The axes of the embrasures are then staked out, the breadth, hh, of the bar- 

 bettes, A, marked off"; between them the ditches, mo, running towards W, 

 and on the outside of the two outer pieces the twelve-feet wide ditches, sty 

 running in the same direction, are dug out. Having arrived at t and o, 38 

 ieei from GH, the whole mass of earth, U, lying in rear of the battery, is 



645 



