tenths of a foot in a northeasterly direction was found. This dif.
ference may have been caused by physical displacement of the monument.
The Los Angeles Office of the U. S. Coast and Geodetic Survey concurred in the conclusion that station North Base could not be accepted
as being in its true position and in the decision to measure the lines
from the present position of station North Base to station Runit to establish a base line for the present survey. The geographical position of
Station Runit and the azimuth of the line from station Runit to station
Ceral could be accepted for position and azimuth because the limited axtent of the adjustments involved would not appreciably affect the accuracy
requirements of this Project.
FIELD PROCEDURE FOR PRIMARY CONTROLS

A reconnaissance was made of all locations involved, and markers

were set for the triangulation stations.

Actual observing on this survey

was begun in October 1949.

The observing party consisted of an observer, a recorder, and a
varying number of light tenders. The party was quartered on a LCT, which
moved to convenient points in the lagoon as required. An LOM and DUKW
were used for transportation to the stations and, when practical, planes
were used between the islands having landing strips.
Four Bilby steel towers were available for the survey and were moved
from station to station as the survey progressed. Where low towers could
be used, they were constructed of wood.

and little vibration was experienced,

Towers were adequetely braced,

All observing was done at night with a Wild T-2 theodolite, which

proved very satisfactory, although some difficulty was experienced with
interior lighting, probably because of moisture. Station lights were Navy
battle lamps with rheostats installed so that light could be dimmed to
proper intensity. They made very satisfactory targets.
Because of the remote location of the stations, continous interstation communications were maintained by Ammy Type 619 portable radios.
Instant adjustments in light intensity were thus made possible, and considerable time was saved in communicating instructions and changes in

plans often made necessary by changing weather conditions.

To take advantage of favorable weather, the survey had been sched-

uled for early summer; but delays in receiving specialized equipment and
in constructing the new station in the lagoon postponed observing so that

considerable rain and high wind interfered with access to the stations

and visibility,

Water transportation was adequate but recessarily slow, and the men

were usually away from the base of operations for fourteen to sixteen

hours a day. Because during the early phases of the Project travel after
dark in the lagoon was considered dangerou:, the men were landed before
dark in the evening and picked up after sunrise in the morning.

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