\fdO'^ - Old Forge Coal Mines

262 LAND SURVEYING.
Taking the first proportion, we have 37.20 ch., the sum of
all the distances : 10.40 ch.j the first distance :: 3 links, the
total error : 1 link, the correction for the first distance.
The latitude of the first course, viz., 8.87 ch., is north, and
as the sum of the north latitudes is the greater, we subtract
the correction leaving 8.86 chains. The correction for the
latitudes of the second course is 1 link, and is likewise sub-
tracted. The correction for the third course is less than 1
link, and is ignored. The correction for the latitude of the
fourth course is 1 link, and as the sum of the south latitudes
is less than the north latitudes we add the correction. We
place the corrected latitudes in the eighth and ninth columns.
In a similar manner we correct the departures, as
shown in the above proportions, placing the corrected
departures in the tenth and eleventh columns.
(738) We rule three columns as shown below, the first
column for stations, the second for total latitudes from Sta.
2, and the third for total departures from Sta. 2. Station 2
being a point only, its latitude and departure are 0. The
latitude of the second i. course, e., from Sta. 2 to Sta. 3,
is + 4.31 chains, and the departure -|- 8.12 chains. These
distances we place opposite Sta. 3, in their proper columns.
The latitude of the third course, i. e., from Sta. 3 to Sta. 4,
is— 6.15 chains, and the departure -f 4.46 chains. There-
fore, the total latitude from Sta. 2 is the sum of -j- 4.31
and — 6.15, which is— 1.84 chains. The total departure
from Sta. 2 is the sum of + 8.12 and -f 4.46, which is + 12.58
chains. These totals we place opposite Sta. 4 in their
proper columns. The latitude of the fourth course, i. e.,
from Sta. 4 to Sta. 1, is — 7.02 chains, and the departure
— 7. 14 chains. These quantities we add with their proper
signs to those previously obtained, which give us the total
latitudes and departures from the initial Sta. 2, and we
have, for the total latitude of Sta. 1, the sum of — 1.84
and — 7.02, which is — 8.86 chains, and for the total departure
the sum of + 12.58 and — 7.14, which is + 5.44 chains.
The latitude of the first course, i. e., from Sta, 1 to Sta. 2,