Twenty-three dehumidification units were ordered in accordance with the new specifications for use in the following stations: On Engebi: 2 units in Station 6a, 2 units in Station 6b, On Aomon Group: 2 units in Station 6a, 2 units in Station 6b, On Runit: 2 units in Station 6a and 2 units in Station 6b, On Parry: 2 units as spares, 1 unit in Station 132a, and 3 units in Station 132b. 2 units in Station 132a, and 3 units in Station 132b. Drawings were prepared for dehumidification units for Stations 6a, 132a am 132b on Bogallua and an order was placed on August 4, 1950, On August 14, 1950, AEC advised that Bogallua would not be used as an experiment islamd and the order wes cancelled, In accordance with instructions from Los Alamos on October 16, 1950, planning was started in preparation for a second experiment on Engebi with the tower located on the northeast corner of the island, Stations 6a, 6b, and 132b were to be used a secomd time in connection with the second experiment, The dry condensing and compressor units were located outside these stations and would be expended. Seven additional dry condensing and compressor units were ordered by H & N on October 26, 1950 as replacements for the expended equipment. AIR CONDITIONING As stated previously, the only building to be air conditioned was the photo laboratory on Parry. It was determined that in this building it would be necessary to maintain a temperature of 70°F with 50 per cent relative humidity. This was accomplished by using the same equipment which had been designed and used for dehumidification, The only difference in the use of this equipment was that when it was used as an air-conditioning unit, it was necessary to control air temperature as well as relative humidity. Extensive duct work was required because the building was broken up into many small darkrooms which were com- pletely lighttight and airtight. VENTILATION Ventilation work for buildings was started early in October of 1949, the first unit being the mess hall exhaust hoods, As this work progressed, it became necessary for H & N to design special equipment to handle the job because of unusual conditions to which the equipment would be exposed and because of the importance of its operation at all times, The power roof exhausters were of aluminum construction, complete with weatherproof cap. The fan was driven by a fungusproof and moistureproof electric motor mounted outside the airstream and protected by a 5-259