Evening star. [volume] (Washington, D.C.) 1854-1972, 1913-02-09


claim to any considerable
Iechnlcal age, with perhaps sin
uo4.r. gle exception. That is the
United States coast and
gcodetic survey, which,
upon the recommendation of Thomas JEFF
ferson, was authorized by Congress in
1907
At that time it was merely a national
coast survey. and formed a part of the
Treasury Department. No work was
done. however. until 1911, when prepara-
tons were begun, and the actual field
work undertaken i'll 1916. From ISIS
until 1892 the work was suspended In
1871 the bureau was enlarged and in
1877 it became the coast and Geodetic sur
vey. In 1903 it was transferred to the
newly established Department of Com
merce and Labor
That is brief outline of what today
represents one of the most important
branches of Uncle Sans machinery. Not
only can this branch of government sery-
ice claim long life. but it has the
further distinction of standing at the
head of the list of similar institutions in
the world
history of the coast and ceodetic sur
vey. written in detail. would be a strik-
ing example of the forward strides
which have been made by science. It
would show concusively that what was
AT one time matter of conjecture
more or less. has been brought almost
to an exact science.
The two duties for which the survey
stands. coast and geodetic surveying, rep
resent two necessary fac
Invaluable tors in the progress of this
c.rr;o. country Without the coast
charts. which are pre-
pared and published by this bureau
ITSELF the lives of those at sea would
be much more endangered than they are
at present. The work of making coast
surveys consists of taking soundings and
otherwise determining the character of
the sea bottom on the coasts of this coun-
try and it's possessions, thereby aiding
navigation generally. The work of max
ing geOdetic surveys consists of making
land surveys which far exceed those Of
the ordinary city surveyor, for instance
in accuracy. and which cover in addi-
ton, greater areas.
The principal means used in making
geodetic surveys Is triangulation, a
method employed in surveying distances
SO great that small distractions or the
natural Curvature of the earth would
interfere. This process rests upon the
geometrical proposition that if one side
and the angles of a triangle are known
the remaining sides can be determined
The distances covered in this method
run from thirty to one hundred and
eighty miles.
An interesting point was brought out
by one of the scientists OF the survey in
explaining the use OF tri-
curvature angulation, in which he
~ yrr.4 showed the necessity of Sc
curing some high point
when any great distance is to be covered.
Take a lake. for instance he said,
which to all appearances is level Place
a stick at any given point in the water
SO that it stands four feet above the
water level Then a mile away place an
other the same height out of the water
For convenience it is we'll to put cross
sticks on the top of these to make them
more noticeable. Then get some one to
stand between these two sticks and place
another so that the top appears in an
exact line with the top of the two others.
When this middle stick is measured 1t
will be found to be only three feet four
inches ont of the water, showing that
there is curvature of eight inches
An ordinary county or city surveyor
considers the subject of his survey, prac-
tically speaking, as being level. The en-
gineer who is making surveys for the
geodetic survey, on the other hand. takes
into the consideration not only the fact
that the earth * round, but also that
its continued revolution tends to make
1t egg shaped. Consequently, he Will
choose a point, say the top of a mouI-
tain. as one corner Of his triangle. with
the two other corners on normal ground.
In a science that is so exact that i:
takes into consideration such points as
the curvature of the earth it is only
natural that the instruments used should
be of extraordinary accuracy. 1t
is also natural that such delicately con-
structed instruments as they must neceS-
sarily be should be expensive. One small
instrument, for example, of which the
survey has fifty, costs nearly $500 while
the larger pieces cost in many cases
more than $1,000 each.
Coast surveys are made principally by
means of soundings and the use of what
is called drag wire.
Surveying Twelve vessels are con-
o. tinually employed in MAX
OooSCS' ing surveys along the
coasts of either the United States or some
of her possessions. In preparing what
eventually becomes survey chart the
first step in the preparati ton of a large
piece of drawing paper with lines crossing
represent longitude and latitude. When
survey is started the first thing
to be done is to ascertain the actual To-
cation of the ship and then TO find its
relative position on this chart. This ac-
complished. soundings are taken. and the
depths recorded in their proper places ON
the chart. In surveying an area OF about
. 900 square miles more than $1,000 or
10000 soundings may be taken. The
chart is then sent to the office in this
city, where it is given into the hands or
computing experts. out OF the 10000 or
$4,000 soundings recorded only few
hundred are eventually used, about per
cent, perhaps, and these nave TO DE
chosen with the utmost care TO insure
their being representative OF the local1ty
to which they refer. Whereas an origl-
nal chart as filled out by the surveyors
themselves is about five by two and one
half feet. when finished it forms but
small portion of chart which may be
only two by three feet. The cost of pre-
pairing such a chart from the initial
step until it is finally printed and ready
for actual distribution Is approximately
100000, or bout so a square mile.
The primary object in making surveys
~ ha