850 millibars. The winds were nearly calm at the surface; at 10,300
feet above mean sea level, they were from the southwest at 10 knots.
The winds blew the cloud resulting from the detonation to the
northeast. From 16 July 1945 through 1946, about 1,000 military and
civilian personnel took part in Project TRINITY or visited the test
site. The location of the test site and its major installations are
shown in the accompanying figures.


Military and Scientific Activities

All participants in Project TRINITY, both military and civilian, were
under the authority of the MED. No military exercises were conducted.
The Los Alamos Scientific Laboratory (LASL), which was staffed and
administered by the University of California (under contract to the
MED), conducted diagnostic experiments. Civilian and military
scientists and technicians, with assistance from other military
personnel, placed gauges, detectors, and other instruments around
ground zero before the detonation. Four offsite monitoring posts were
established in the towns of Nogal, Roswell, Socorro, and Fort Sumner,
New Mexico. An evacuation detachment consisting of 144 to 160
enlisted men and officers was established in case protective measures
or evacuation of civilians living offsite became necessary. At least
94 of these personnel were from the Provisional Detachment Number 1,
Company "B," of the 9812th Technical Service Unit, Army Corps of
Engineers. Military police cleared the test area and recorded the
locations of all personnel before the detonation.

A radiological monitor was assigned to each of the three shelters,
which were located to the north, west, and south of ground zero. Soon