In the second place, all that extent of a rampart or entrenchment, from whence the shot of ordnance or musquetry is discharged, is understood to be a line of fire.
If, for instance, it were to be said that a reserve or oblique direction was taken against a long extent of rampart or entrenchment, by means of a jettée or any great work thrown up, so as to out-flank or take it in the rear, it might be concluded that those points would be supplied with a long line of fire.
Line of direction, (Ligne de direction, Fr.) In mechanics any straight line down which a heavy body descends. There are likewise lines of direction which relate to powers; they are then straight lines by means of which a power draws or urges on a weight for the purpose of supporting or moving it.
Capital Line of the bastion, (Ligne capital du bastion, Fr.) a line which is drawn from the centre angle of a bastion to its flanked angle. In regular fortification this line cuts the bastion in two equal parts.
Lines of entrenchment, (Lignes retrenchées, Fr.) all lines which are drawn in front of a camp, &c. to secure it from insult or surprize are so called. Whenever an army is not sufficiently strong to run the hazard of being attacked, the general who commands it, must have the precaution to dig a ditch in front measuring three toises at least in breadth and two in depth. He must likewise throw up a parapet with redans, or have it flanked at intermediate distances by small bastions two toises thick, made of strong close earth, and get it covered and supported by fascines, with a banquette behind sufficiently high to cover the soldiers tents. If water can be got into the ditch from a neighboring stream or rivulet, an additional advantage will be derived from that accession. When the lines are constructed for any space of time, it will then be proper to make a covert-way in the usual manner.
Other lines are likewise constructed for the purpose of communicating with different quarters; great care must be taken lest any of them be exposed to the enemy’s enfilade. To prevent this they must be supported by redoubts, or by works belonging to the neighboring forts; for the enemy might otherwise make good his ground within them, and use them as a trench.
If an army is so weak as to be within lines, you take care to have communications between the villages, and small parties of light horse patroling towards the enemy, and to have videttes and sentries posted so near one another, that you may have intelligence of all their transactions.
Line in fencing, that part of the body opposite to the enemy, wherein the shoulders, the right arm, and the sword, should always be found; and wherein are also to be placed the two feet at the distance of 18 inches from each other. In which sense, a man is said to be in his line, or to go out of his line, &c.
Line, also denotes a French measure, containing ¹⁄₁₂th part of an inch. It is of late frequently made use of in calculations.
Line of Science, is substituted for the old and awkward oblique step; movements to a flank oblique are now by half or quarter facing, that is, the whole who are to move in the required direction are faced on a line midway between a front and full faced position; so that quarter faced to the right, the right shoulder of the second man is behind the left shoulder of the right file; and so on each along each rank have their right shoulders behind the man on their right: so if the movement is to be oblique to the left, they are quarter faced to the left, and the files will stand successively with their left shoulders in the rear of the right of those who stood on their left.