Program 18. Thermal Radiation. Program 19. Marine Survey. Task Unit 12 - UCRL - Livermore Programs. (Dr. A. J. Hudgins) Program 21. Radiochemistry. Program 22. History of the Reaction. Program 23. Scientific Photography. Program 24. External Neutron Measurements. Program 25. Diagnostic Developments. With the exception of minor changes in various projects; the addition of Project 3.4, "Neutralization of a Planted Sea Mine Field," Project 6.1 "Test of Interim IBDA Procedures for High Yield Weapons," .and Program 4, "Biomedical Studies"; and the elimination of Program 25 in November, the experimental programs schedule was essentiaily firm as of this time. One early decision relative to CASTLE which carried considerable operational significance was the decision to use barges anchored in the lagoon as ground zeros for certain of the detonations. This was in order to reduce contamination, to make better use of the limited amount of real estate available, and to speed up the tests by scheduling assembly operations at the proposed barge slip at Eniwetok, and moving each barge into position about five days before detonatim. This made it possible to plan on using the same zero point, if necessary or desirable, regardless of the high radiation levels to be expected on the islands in the vicinity of the preceding shot. It also permitted late changes in the location of the zero point if operational developments warranted them. 9