MAP. 
likewise the glohnlar projection, in which 
nieridians, equidistant upon tlie surface of 
the earth, are represented by equidistant 
circles in tlie map. Mercator’s projection 
is that in which both the meridians and 
parallels of latitude are represented by 
straight hires. See Chart. 
In all maps the upper part is the norths 
the lower the south, the right hand is 
eastern, and the left hand western. On 
the right and left the degrees of latitude 
are marked; and on the top and bottom 
the degrees of longitude, are marked. When 
the meridians and parallels of latitude are 
straight, and parallel lines, the latitude of a 
place is found by stretching a thread over 
the place, so that it may cut the same de- 
gree of latitude on both sides the map, and 
that degree is the latitude of the place. To 
find the longitude, stretch a thread over 
the place, so that it may cut the same de- 
gree of longitude on the top and bottom, 
and that degree is the longitude of the 
place. When the meridians and parallels of 
latitude are curve lines, then to find the 
latitude of a place, a parallel line of latitude 
must be drawn through it, by the same 
rules as the other parallels are drawn, and 
it cirts the sides at the degree of latitude of 
the place : and to find the longitude of the 
place draw a circle of longitude through it, 
by the same rules as the other circles are 
drawn, and it ents the top and bottom at 
the degree of longitude of the place. We 
shall now proceed to shew some of the most 
familiar constructions of maps, beginning 
with a general map, or map of the world, of 
which there arfe three methods : 
First. A map of the world must repre- 
sent two hemisplieres ; and they must both 
be drawn upon the plane of that circle 
which divides the two hemispheres. The 
first way is to project each hemisphere upon 
the plane of some particular circle, by the 
rules of orthographic projection, forming 
two hemispheres, upon one common base, 
or circle. When the plane of projection is 
that of a meridian, tlie maps will be the 
east and west hemispheres, the other meri- 
dians will be ellijises, and the parallel cir- 
cles will be right lines. Upon the plane of 
the equinoctial, the meridians will be right 
lines crossing in the centre, which will 
represent the pole, and the parallels of lati- 
tude will he circles having that common 
centre, and the maps will be the nortliern 
and southern hemispheres. The fault of 
this way of drawing maps is, that near the 
outside the circles are too near one another ; 
and, therefore, equal spaces on the earth 
are represented by very unequal spaces 
upon the map. 
Secondly. Another way is to project the 
same hemispheres by the rules of stereogra- 
phic projection ; in which way, all the paral- 
lels will be represented by circles, and the 
meridians by circles or right lines. And here 
the contrary fault happens, liz, the circles to- 
wards the outsides are too far asunder, and 
about the middle they are too near together. 
Thirdly. To remedy the faults of the two 
former methods, proceed as follows : 1st. 
for the eastern and western hemispheres, 
describe the circle P E N Q for the meridian 
(Plate Maps, fig. 1.) or plane of projection ; 
tlrcongh the centre of which draw the equi- 
noctial, E Q, and axis, P N, perpendicular 
to it, making P and N the north and south 
pole. Divide the quadrants P E, E N, N Q, 
and Q P, into 9 equal parts, each represent- 
ing 10 degrees, beginning at the equinoctial 
E Q : divide also C P and C N into 9 equal 
parts, beginning at E Q ; and through the 
corresponding points draw the parallels of 
latitude. Again, divide C E and C Q into 
9 equal parts ; and through the points of 
division, and the two poles P and N, draw 
circles, or rather ellipses, for the meridians. 
So shall the map be prepared to receive the 
several places and countries of the earfh. 
Sndly. For the north or south hemisphere, 
draw A Q B E, for the equinoctial (fig. 2), 
dividing it into the four quadrants EA, 
A Q, Q B, and B E ; and each quadrant into 
9 equal parts, representing each 10 degrees 
of longitude ; and then, from the points of 
division, draw lines to the centre, C, for the 
circles of longitude. Divide any circle of 
longitude, as the first meridian, E C, into 9 
equal parts, and through these points de- 
scribe circles from the centre, C, for the 
parallels of latitude ; numbering them as in 
the figure. 
In this third method equal spaces on the 
earth are represented by equal spaces on 
the map, as near as any projection will 
bear; for a spherical surface can no way be 
represented exactly upon a plane. Then 
the several countries of the world, seas, 
islands, sea-coasts, towns, &c. are to be en- 
tered in the map, according to their lati- 
tudes and longitudes. 
In filling np the map, all places represent- 
ing land are filled with such things as the 
countries contain ; but the seas are left 
white; the shores adjoining to the sea being 
shaded. Rivers are marked by strong lines, 
or by double lines, drawn winding in form 
R 2 
