28 MILITARY COMMISSION TO EUROPE. 



Merlons, T' to 8' high, 17^' to 21' from axis to axis of the embrasures. 



Barbettes, 3' to 3' 3" below the interior crest, 17^' to 24' deep, 14' wide. 



Gun and howitzer platforms, 9' wide, 17^' to 21' long. 



Mortar •platform, 7' wide, 7' to 9' long. 



A gun or howitzer platform consists of: 1st, a hurter, not less than 9' long X 6" square, it is 

 bisected at right angles by the directrix ; 2nd, 3 or 5 sleepers, (according to the soil,) not less than 

 6" square, and as long as the platform ; the outside sleepers are 5J' apart from centre to centre, 

 and are parallel to each other ; 3rd, flooring planks not less than 2" thick. 



K mortar platform consists oi: 1st, 3 sleepers 8" square and as long as the platform; 2nd, 

 flooring timbers 7' long and 8" thick. 



ARRANGEMENT OF THE WORKING PARTY ON A FIELD WORK. 



From four to five men are assigned every six running feet of the ditch, according to the strength 

 of the profile. In easy soil each of these parties has one pick or mattock, four shovels, and one 

 earth rammer ; in difficult soil there should be two-thirds shovels and one-third picks ; in very 

 difficult soil, one-half shovels and one-half picks. 



The workmen are placed in four ranks, which are 6' apart; the first rank in the ditch, near 

 the counterscarp; the second at the middle of the ditch, opposite the intervals of the first rank; 

 the third on the berm ; the fourth on the parapet. 



The first rank carry their excavation to the depth of 3', from the counterscarj) to the middle of 

 the ditch, and throw the earth on the berm; the second rank work from the middle of the ditch 

 towards the scarp, throwing the earth on the berm and parapet ; the third rank throw the loose 

 earth from the berm towards the interior slope ; the fourth rank level the earth on the parapet, 

 ram it, form the slopes, &c. If the ditch is more than 10|' wide, the first rank throw their 

 earth towards the scarp, whence the second rank throw it on the berm. The scarp and counter- 

 scarp are at first cut down in steps, being afterwards trimmed off to the proper slopes. 



Any superfluous earth is fotmed into a glacis. 



In a ditch not more than 4' deep, in good soil, two men can in ten hours excavate and shovel 

 off 343 cubic feet ; in a ditch from 4' to 5^' deep, one additional man is required to do the same 

 work; in a ditch more than 5|' deep, four men, two of whom have barrows or baskets, are 

 required to do the same work. The interior slope is always revetted with fascines or hurdles, in 

 default of these with sods. The exterior slope is revetted with fascines or hurdles only when the 

 parapet is of sand. 



When the work is to stand for some time, the exterior slope and the counterscarp may be 

 revetted with sods. 



Parties of seven sappers each are detailed to revet the interior slope ; the three oldest soldiers 

 arrange the slope, the other four bring up the materials. Each party should revet 24 running 

 feet, and is provided with one iron hammer, one bill-hook, and 1 handsaw. 



SECONDARY MEANS OF DEFENCE. 



Inundations should not be less than 5' deep. 



Chevaux-defrise. — Body of square timber, 9' long ; the lances project 5', are 1^" in diameter, 

 aud 9^" apart. 

 Palisades. — Of round timber, 9|' to 10^' long, 8" in diameter; point, 1' long; butts charred. 



