s 62 
GEOGRAPHY. 
20 - - 
- - 25 
30 . . 
- - 42 
40 - - 
- - 61. J 
JO . . 
. - - 88 
60 - - 
- - 133 
70 - . 
- - 208 
80 - - 
- - 464 
found mechanically, by the following table : let the 
radius of tlie circle EC, be divided into loo equal parts, 
by a fcale : then the circle of 
io°will be equal to 12 r ./•.«• 
^ ~ of thofe parts fet off, 
from C towards 
added to thediftance 
^between C and the 
feveral points, 10, 
20, 30, See. in the ra¬ 
dius E C. 
Thus the radius of the circle of 10 degrees of longi¬ 
tude is equal to the diflance between 10 in the line E C, 
and 10 in the line QJD ;—of that of 50 degrees between 
50 and JO;—and that of 80 degrees, between 80 in the 
line EC, and a given point in EQ^produced, which 
taken from C, will be equal to 342-2 parts, of which 
the radius is equal to 100. 
By this method, equal fpaces on the earth are repre- 
fented by equal fpaces on the map, as nearly as any pro- 
jeftion will admit; for a fpherical fiirface, as before 
noted, can by no poffible method be reprefented exatlly 
upon a plane. And now the feveral countries of the 
world, the feas, illands, towns, &c. are to be entered on 
the map, according to their known latitudes and longi¬ 
tudes.—Thus the map of the world, difplaying the two 
hemifpheres, as given in this treatife, is conflrudted upon 
the globular projedfion. 
In completing maps of countries, all places reprefent- 
ing land are diftinguifhed with fuch objefls as the feveral 
countries contain, as mountains, forefts, &c. but the 
feas are left white, edged with a green tint; the hiores 
adjoining the fea being (haded, more or lefs, as a flat, 
or a bold lliore may occafionally require. Rivers are 
marked by ftrong lines, or by double lines, drawn wind- 
ing in the form of the rivers they reprefent, and fmaller 
rivers are exprelfed by fmaller lines. Different countries 
are bed diftinguifhed by different colours; forefls by 
trees, and mountains (haded, to give them their lofty 
effedt. Sands are denoted by fmall points or fpecks; 
and rocks under water by a fmall crofs. 
To draw a map of any given portion of the earth. —Suppofe 
it be required to draw a map of a portion of the earth’s 
furface containing fix degrees of latitude, viz. from the 
39th to the 4jth degrees: draw the line E F, in the 
Geography Plate II. fig. 8 ; and in the middle raife the 
perpendicular D C, which divide into fix equal parts, 
or degrees of latitude, and through C draw a line pa¬ 
rallel to E F.—Next divide a degree into 10; or if large 
enough, into 60 equal parts; and in the annexed table 
find the number of miles which a degree of longitude 
contains, in the latitude of 39 degrees, viz. 46*62, and 
from any fcale of equal parts, fet off one halfof the fame, 
viz. 23*31, on each fide of D.—Then find in the table 
the number of miles contained in a degree of longitude 
in the latitude of 45 degrees, viz. 42*43, and from the 
fame fcale fet off 21*215 on each fide of C. Draw the 
ffraig.ht lines from I to E, and from K to F; divide them 
into the fame number of parts as the line C D contains, 
and through the points di'aw parallel lines. Thus 
J K EF is a projediion for one degree of longitude, in¬ 
cluding fix degrees of latitude. 
Since the degrees mufi be lo drawn that the two dia¬ 
gonal lines in each mufi: be equal to each other, they are 
to be projected in the following'manner: Firft, take the 
difiance from E to K, dr from F to I, and fetting one 
foot of the compafl’es firfi in E and then in F, deferibe the 
arcs L and M. Then let one foot firfi in I, and after¬ 
wards in K, and with the fame extent draw the arcs N 
and O. Secondly, take the diltance between E and F, 
and fet it off in the arcs deferibed from E to N, and from 
F to O ; then take the difiance between I and K, and fet 
it off from I to L, and from K to M. Thirdly, draw the 
lines between t and N, and M and O ; divide them into 
degrees, and draw parallels from thofe points to the 
correfponding ones in the meridians I E, and K F. The 
fame method mufi be purfued in drawing.all the other 
meridians and parallels, as the map is to contain degrees. 
If the map be very large, fo that the compalTes will not 
extend to thefarthefi degree, or fromF to I; then draw 
one or more diagonals at once, and afterwards proceed 
with the refi.—Thus when the fquares P G N E and H 
F O are deferibed, LIP G and IC MH Q. may be done. 
Number the degrees of latitude up both fides of the 
map, and the degrees of longitude on the top and bot¬ 
tom, as before directed; then make the properdivifions 
and fubdivifions of the country; and having the lati¬ 
tudes and longitudes of the principal places, it will be 
eafy to fet them down in the map, by the methods ex¬ 
plained above; which (hew that every town, &c. mufi 
be placed where the circles of longitude and latitude 
interfeft. Thus, if the map contain that part of Europe 
that lies between 39 and 45 degrees of latitude, and be¬ 
tween 7 and 16 degrees of eafi longitude, then Florence 
mufi be placed at A, where the circles of 43° 46' 30" 
north latitude, and 11° 3'30" eafi longitude, cut each 
other: and Naples mufi be placed at B, on the fea-fiiore, 
at 40°50' 15" N. lat. and 14° 17' 30" E.lon. 
In like manner the mouth of a river, as of the Tiber 
for infiance, mufi be fet down; but to deferibe the 
whole river, the latitude and longitude of every turning 
fliould be marked down, and the towns and bridges by 
which it pafies. In the projeflion here deferibed, the 
diagonals being all equal, the number of meridians 
caufes no defedt in the reprefentation, as equal fpaces on 
the globe are reprefented by equal fpaces on the map ; 
confequently places lying in the remotefi degrees of 
longitude, are as truly exhibited as thofe near the mid¬ 
dle, and their difiances will agree with a common mea- 
fure; fo that compaffes extended between any two 
places, and applied to the fcale, give the difiance with¬ 
out farther trouble.—Indeed, there fliould be a fcale of 
miles, or of degrees, on every map, to ferve for finding 
the difiances of places on it. It is ufual alfo to draw 
the mariner’s compafs or a fleur de lys, to (hew the 
points of the compafs. 
TAB LE,ftewing the number of miles contained in a degree of Ion. 
gitude, in each parallel of latitude, from the equator to the poles. 
Degrees of 
Latitude. 
Miles 
100th parts 
I of a mile. 
Degrees of 
Latitude. 
Miles. 
looth parts 
1 of a mile. 
[ Degrees of 
Latitude. 
Miles 
100th parts 
1 of a mile. 
1 
59 
96 
31 
51 
43 
61 
29 
04 
2 
59 
94 
32 
50 
88 
62 
28 
17 
3 
59 
92 
33 
50 
32 
63 
27 
24 
4 
59 
86 
34 
49 
74 
64 
26 
30 
5 
59 
77 
35 
49 
15 
65 
25 
36 
6 
59 
67 
36 
48 
54 
66 
24 
41 
7 
59 
56 
37 
47 
92 
67 
23 
45 
8 
59 
40 
38 
47 
28 
68 
22 
48 
9 
59 
20 
39 
46 
6-2 
69 
21 
51 
10 
59 
08 
40 
46 
00 
70 
20 
52 
I I 
5S 
89 
41 
45 
28 
71 
^9 
54 
I 2 
58 
68 
42 
44 
95 
72 
18 
55 
13 
5 * 
46 
43 
43 
88 
73 
17 
54 
14 
58 
22 
44 
43 
16 
74 
16 
53 
15 
58 
. 00 
45 
42 
43 
75 
25 
52 
16 
57 
60 
46 
41 
68 
76 
14 
51 
17 
57 
30 
47 
41 
00 
77 
13 
50 
18 
57 
04 
48 
40 
15 
78 
12 
48 
19 
56 
73 
49 
39 
36 
79 
II 
45 
20 
56 
38 
50 
38 
57 
80 
10 
42 
21 
56 
00 , 
51 
37 
73 
81 
09 
38 
22 
ss 
63 
52 
37 
00 
82 
08 
35 
23 
55 
23 
53 
36 
18 
83 
07 
32 
24 
54 
81 
54 
35 
26 
84 
06 
28 
25 
54 
38 
55 
34 
41 
85 
05 
23 
26 
54 
00 
56 
33 
55 
86 
04 
18 
27 
53 
44 
57 
32 
67 
87 
03 
14 
28 
53 
00 
58 
31 
70 
88 
02 
09 
29 
52 
48 
59 
30 
90 
89 
Ol 
05 
30 
51 
96 
60 
30 
00 
90 
00 
00 
When 
