Evening star., 1915-07-15
MAPS.
LIN the Making.
By Frederic J. Haskin.

The work of the map maker is not
a dull and monotonous career. as
might be supposed. 1t may be full OF
thrills and adventures. of discomfort
and physical strain. of dangers sell
dom equaled in any other calling. and
certainly not often eXcelled. Most or
the official map makers of the United
States are under the jurisdiction of the
geological survey. Each spring they
start out in parties. each under the di-
rection of topographic engineer, and
the field work is pursued as long as
the weather permits. The winter is
spent in preparing the maps from the
information ard charts that were
sketched during the summer
A typographical field trip is mo sum-
mer picnic, as most people suppose,
according to one of the most expert
enced men enrolled. The men who go
out upon them encounter many hard
ships. Sometimes they are obliged to
linger for days in pestilential swamps.
At other times they work upon track
less deserts or upon high mountains.
The mountain surveys are the most
dangerous. A man may have to hang
out over a steep precfpice to make OBJ
servations, having only the root of an
overhanging tree to keep him from be-
ing dashed to death in the great abyss
below. The dangers of the steeple
climber upon a high building, when the
is provided with the best mechanical
equipment for his protection, are small
compared with those of the car
tographer making surveys for new
maps in the Rocky mountain regions
He has no protection but that provid-
ed by his own ingenuity and he cannot
know beforehand just what conditions
he is to encounter.
Last year party Of photographers
-
encountered terrific blizzard, during
which several men were permanently
crippled by badly frozen hands and
feet. They had not the clothing neces-
| sary for their protection in extreme
| cold so Unexpectedly encountered.
X +
neers and large number of temporary
assistants engaged
Big Force for field work dur
Mapping U. S. kept lng 'ns as yumfn woph fn re. re-.
mapping the entire United States. Their
work progresses at the rate of about
10000 square miles year. Nearly 4O
per cent of the area has now been COW
cred, and over 1900 base maps pub
lished.
The surface Of the earth is constantly
changing, so that even If a map is ab-
solutely accurate at the time 1t is
made, it may become more or less IN
correct within a few years. Most OF
thas. OBJ Eges are due to magnetic cur
rc-sa. Z d are being overcome by in
cr>axsng knowledge of terrestrial mag.
netism. This knowledge is due almost
entirely to the munifcence of the Car
negie Institution of washington. wnich
is establishing terrestrial magnetic sta
tions throughout the world.
Close cooperation in map making Is
maintained between the geological
survey, the land office. the Department
of Agriculture. the Post Office Depart
ment and a few other divisions Of gov
eminent which make occasional maps
for some special purpose The Post
Office Department surveys counties and
rural districts about which additional
knowledge is desired for establishing
mail routes. The land Office has made
surveys for irrigation porjects which
require maps Of particular class.
The Department of Agriculture uses
innumerable maps in its graphic por-
trayal Of facts. Most of them are