CHART. 
a tide, an anchor without a stock is to he 
laid down. The soundings, tlie quality of 
tlvi ground, the times of iiigh water at full 
and change, &c. are to be marked in their 
proper places. _ . 
Charts, mnnner of using. — The princi- 
pal use of a chart is, to find the course and 
distance between any two places within its 
limits, and to lay down the place of a ship 
on it, so that the position of the ship with 
respect to the intended port, the adjacent 
land, islands, &c. may be readily per- 
ceived. 
To find the latitude of a place on the Chart. 
Rule. — ^Take the nearest distance be- 
tween the given place and Ihe nearest pa- 
rallel of latitude, which being applied the 
same way on the divided meridian, from the 
point of intersection of the parallel and 
meridian, will give the latitude of the pro- 
posed place. 
Example. — Required the latitude of Port 
Louis, in the Isle of France. The least dis- 
tance between Port Louis and the iieaiest 
parallel, being laid the same way on the 
meridian, from the extremity of that pa- 
rallel, will reach to 20° 8' S,, the latitude 
required. 
To find the course and distance between two 
given places on the Chart. 
Rule. — Lay the edge of a scale over the 
given places, and take the nearest distance 
between the centre of any of the compasses 
on the chart and the edge of the scale ; 
move this extent along, so as one point of 
the compass may touch the edge of the 
scale, and the straight line joining the points 
may be perpendicular tliereto ; then will 
the other point show the course ; and the in- 
terval between the places being applied to 
the scale will give the required distance. 
JSMmple.— Required the course and dis- 
tance from Cape St. Andrfe to Cape St. 
Sebastian, both in the island of Madagascar. 
The edge of a scale being laid over the two 
places, then, by moving the compass as 
directed, the course will be found to be 
N. E. 1 E., and the interval between them 
will measure 105 leagues. 
The course and distance sailed from a known 
place being given, to find the ship’s place 
on the Chart. 
Rule. — Lay the edge of a scale over the 
place sailed from, parallel to the . given 
course ; then take the given distance from 
tlie scale on the chart, and lay it off from 
the given place by the edge of the scale, 
and it w'ill give the point on tlie cliart re- 
presenting the place on the ship. 
Example. — The correct course of a ship 
from Cape St. Maria, on the N. side of the 
entrance of the river La Plata, was N. E. by 
E., and the distance 238 leagues. Required 
the place of the ship on the chart. The 
edge of the scale being laid over Cape St, 
Maria, in a N. E. by E. direction, and the 
distance 238 leagues, laid off from Cape St. 
Maria by the edge of the scale, will give 
the place of the ship, which will he found 
to be in the latitude 28“ la S. 
To find the longitude of a place on the 
Chart, 
Rule. — Take the least distance between 
the given place and the nearest meridian, 
which being laid oft’ on the equator, or di- 
vided parallel, from the point of intersec- 
tion of the parallel and meridian, will give 
its longitude. 
Example. — Required the longitude of 
Funchal in the island of Madeira. The 
least distance being taken between Funchal 
and the nearest meridian, and laid off from 
the intersection of that meridian with the 
divided parallel, will give 17“ 6' W., the 
longitude required. 
To find the distance between two given places 
on the Chart. 
1. 'VFhen the given places are under the 
same meridian. 
Rule. — Find the latitude of each ; then, 
the difference or sura of their latitudes, ac- 
cording as they are on the same, or on op- 
posite sides of the equator, will be the dis- ■ 
tance required. 
Example.— Reepured the distance be- 
tween the nearest extremities of the islands 
of Grenada and Guadaloupe. 
Latitude of southernmost ex- 
tremity of Guadaloupe ... 15“ 52' N. 
Latitude of northernmost ex- 
tremity of Grenada 12° 14' K. 
Distance 3“ 38 :^ tl8 M . 
2. When the given places are under the 
same parallel. 
Rule.— If that parallel is the equator, 
the difterence, or sum of their longitudes, 
is the distance between them. If not, take 
half the interval between tlie given piaffes, 
lay it off on the meridian on each side of 
the given parallel, and the intercepted de- 
grees will be the distance between the 
