LINE. 



any manner on the geometrical plane. 2. 

 Terrestrial line, or fundamental line, is a 

 rig-lit line, wherein the geometrical plane, 

 and that of the picture or draught, inter- 

 sect one another, formed by the intersec- 

 tion of the geometrical plane, and the 

 perspective plane. 3. Line of the front, 

 is any right line parallel to the terrestrial 

 line. 4. Vertical line, the common sec- 

 tion of the vertical and of the draught. 

 5. Visual line, the line or ray imagined 

 to pass from the object to the eye. 6. 

 Line of station, according to some wri- 

 ters, is the common section of the verti- 

 cal and geometrical planes. 7. Objective 

 line, the line of an object from whence 

 the appearance is sought for in the 

 draught or picture. 



LINES, in dialling, are, 1. Horizontal 

 line, the common section of the horizon 

 and the dial plane. See DIALLING. 2. 

 Horary lines, or hour-lines, the common 

 intersections of the hour-circles of the 

 sphere, with the plane of the dial. See 

 HORARY. 3. Substylar line, that line on 

 which the style or cock of a dial is duly 

 erected, and the representation of such 

 an hour circle as is perpendicular to the 

 plane of that dial. 4. Equinoctial line, 

 the common intersection of the equinoc- 

 tiat and plane of the dial. 



LINK of measures, is used by Oughtred, 

 to denote the diameter of the primitive 

 circle in the projection of the sphere in 

 piano, or that line in which the diameter 

 of any circle to be projected falls. In 

 the stereographic projection of the sphere 

 in piano, the line of measures is that line 

 in which the plane of a great circle per- 

 pendicular to the plane of the projection, 

 and that oblique circle which is to be 

 projected, intersects the plane of the 

 projection ; or it is the common section 

 of a plane passing through the eye point 

 and the centre of the primitive at right 

 angles to any oblique circle which is to 

 be projected, and in which the centre 

 and pole of such circle will be found. 



LINE of direction on the earth's axis, in 

 the Pythagorean system of astronomy, the 

 line connecting the two poles of the eclip- 

 tic and of the equator, when they are pro- 

 jected on the plane of the former. 



LINE of direction, in mechanics, that 

 wherein a body actually moves, or would 

 move, if it were not hindered. It also de- 

 notes the line that passes through the 

 centre of gravity of the heavy body to 

 the centre of the earth, which must also 

 pass through the fulcrum, or support of 

 the heavy body, without which it would 

 fall. 



LINE of gravitation, of any heavy body, 



a line drawn through its centre of gravi- 

 ty, and according- to which it tends down- 

 wards. 



LINE of the sitnflest descent, of a heavy 

 body, is the cycloid. See CYCLOID, 



LINES on the plane scale, are the line of 

 chords, line of sines, line of tangents, line 

 of secants, line of semitangents, line of 

 leagues; the construction and application 

 of which, see under MATHESIATICAL IN- 

 STRUMENTS, SAILING, Sec. 



LINES on Gunter^s scale, are the line of 

 numbers, line of artificial sines, line of ar- 

 tificial tangents, line of artificial versed 

 sines, line of artificial sines of rhumbs, 

 line of artificial tangents of the meridian 

 line, and line of equal parts ; for the con- 

 struction and application whereof, see 

 GUNTER'S scale. 



LINES of the sector, are the line of equal 

 parts, or line of lines, line of chords, line 

 of sines, line of tangents, line of secants, 

 line of polygons, line of numbers, line of 

 hours, line of latitudes, line of meridians, 

 line of metals, line of solids, line of 

 planes ; for the construction and use 

 whereof, see SECTOR. 



LINES, in fortification, are those of ap- 

 proach, capital, defence, circumvallation, 

 contravallation, of the base, &,c. See AP- 

 PROACH, &c. 



To LINE a ~vcrk, signifies to strengthen 

 a rampart with a firm wall ; or to encom- 

 pass a parapet or moat with good turf, 

 &c. 



LINE, in the art of war, is understood 

 of the disposition of an army, ranged in 

 order of battle, with the front extended 

 as far as may be, that it may not be flank- 

 ed. See AIOIY. 



LINE of battle, is also understood of the 

 disposition of a fleet on the day of en- 

 gagement, on which occasion the vessels 

 are usually drawn up as much as possible 

 in a straight line, as well to gain and keep 

 the advantage of the wind, as to run the 

 same board. 



LINE, ship of the, a vessel large enough 

 to be drawn up in the line, and to have a 

 place in a sea-fight. See SHIP. 



LINE, in fencing, that part of the body 

 opposite to the enemy, wherein the shoul- 

 ders, the right arm, and the sword, ought 

 always to be found ; and wherein are also 

 to be placed the two feet, at the distance 

 of eighteen 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 of the synodical, in reference to 

 some theories of the moon, is a right line 

 supposed to be drawn through the cen- 

 tres of the earth and sun ; and, if it be 

 produced quite through the orbits, it js 



