168 MILITARY SCIENCES. 



3. Construction of Batteries. For the building of the requisite batteries 

 and the work of the trenches, various implements and materials are required, 

 which are represented on pi. 50. To these belong the tracing-line (fig. 7), 

 the mason's level (fig. 8), the square {fig. 9), the plummet {fig. 10), the 

 mattock {fig. 11), the spade {fig. 12), the hand-rammer {fig. 13), the two- 

 man-rammer {fig. 14), and the scraper {fig. 15) for levelling the slopes. 

 Gabions {fig. 18) are made by setting up the requisite number of stakes, in 

 a circle of the proper dimensions, in the earth, and then interweaving them 

 with flexible twigs {fig. 16*, view, fig. 16 ^ ground plan). Sometimes in 

 the weaving, wooden circles {fig. 17 *) are intermingled, whereby the work 

 goes on more rapidly. The basket being finished, the upper layer is bound 

 with withes {fig. 17 **), so that the basket-work may not come out. Every 

 gabion has two anchors {fig. 19) to fasten it in the earth. Fascines {fig. 

 23^*) are made upon a fascine-horse {fig. 20), of slender and straight brush- 

 wood, fifteen feet long and one foot in diameter, and bound at every fifteen 

 inches with withes. For this purpose they are choked upon the choking- 

 frame {fig. 21) by means of the fascine-choker {fig. 22), and tied imme- 

 diately, close to the choke. Sap-fagots {fig. 23 *) are only three feet long ; 

 at a and b they are tied, and a picket-stake is thrust through them. Sand- 

 bags are of canvas, and filled with sand ; are one or two feet long, and one 

 foot thick ; they are of various forms {fig. 24^•^ and^^. 25). 



Siege batteries divide into first and second batteries. The first are to 

 silence the enemy's fire, and destroy his means of defence ; the last are to 

 eflTect breaches. If the front of a battery forms various salient and re-enter- 

 ing angles, it is called an indented battery, or battery en cremaillere, A B 

 {fig. 46) ; but if part of the battery, A B {fig. 47), say fg h, must lie further 

 back than i k, it becomes a broken battery. Is the ground boggy, and a 

 battery to be established behind the dike A {fig. 2), then the wooden bar- 

 bette, ab, is constructed, and we have a scafl^old battery. Masked batteries 

 are those whose embrasures are first opened when their fire commences. 

 If the ground rises terrace-formed, and upon the higher part, a b {fig. 1), 

 some pieces are placed, such a battery is said to be in tiers. If the terre- 

 plein, ab {fig. 37), forms the floor of the battery, it is a horizontal ; but if 

 its floor lies below that, it is a sunken battery {fig. 33) ; and a raised bat- 

 tery when its pieces stand higher than the horizon, A battery which stands 

 perpendicularly opposite the point fired upon is a direct, every other an 

 oblique battery. The pieces stand in the batteries from 12 to 18 feet distant 

 from each other, and there must be from eight to ten feet clear space in 

 rear of them. In the breaching batteries, however, the pieces stand closer. 

 The thickness of the parapet is, according to the consistency of the earth, 

 from twelve to twenty feet, and its height for horizontal batteries from six 

 to eight feet. The embrasures are either half or wholly cut out. PI. 50 

 figs. Q6 and 27, are wholly cut out ; fig. 33 shows one half cut out, the sole? 

 if, meeting the superior slope at /, and the wedge, x, not being removed. 

 The ricochet and howitzer batteries receive such embrasures, as they fire 

 only in high curves. The earth for the batteries is obtained from the 

 ditches, U {fig. 30), excavated in their front and rear. Is a battery so 

 644 



