dehumidify continually and would automatically hold the temperature constant within the specified range, control box built into the unit. All controls were located in a Insofar as was practicable, the equipment was constructed of non- corrosive materials, and all] electrical equipment, where possible, was noistureproof and fungusproof. The units were constructed of aluminum external structural members with interior enclosed panels of 45 Alclad aluminum. and frames, The filters were of the cleanable type with aluminum media All duct work was constructed of aluminum as were duct hangers, grills, registers, and celling outlets. Asbestos cloth was used for the flexible duct connections, and fibre glass was used for the duct installation, with two coats of oil base paint applied after installation. As a result of an invesitgation of many materials, H & N decided that under existing climatic conditions built-up insulation, consisting of tar paper, jute string, hair felt, and friction tape was best suited for refrigerant suction lines. Specifications and invitation for bids on dehumidification equipment were sent to bidders on January 3, 1950, and proposals were opened on January 10, 1950. Because of the import- ance of the unite in regard to the functioning of scientific instruments which were the heart of the tests, a thorough investigation was made of the two loweat bidders, and as 4 result the work was awarded to the second lowest bidder. This order covered 12 dehumidification units for six buildings on Parry, one building on Eniwetok, and one spare unit. Holmes & Narver continued to recieve design criteria from J- Division and additional units were ordered until twenty-eight dehumidification units were ordered from the initial specifications, These in- cluded 18 units used for the buildings on all sites; 8 units for Stations 13la, 135, 14lb, lide and b, on Engebi and the Aomon Group; and 2 units assigned to Parry for use as spares. Additional design criteria received in February 1950, gave authorization to proceed with the rehabilitation of the existing Stations 6a and the design of a similar Station 6B adjacent to existing stations for Runit, Aomon, and Engebi. All stations were to be dehumidified and a survey made at the Jobsite indicated that the existing dehumidification unite at these sites were beyond economical repair. Design loads were calculated and dehumidification equipment designed similar to the design of the previous units and in accordance with J-Division's request to mount the dehumidifier inside the station .and the dry condenser outside. Dehumidification equipment specifications were altered to describe the new equipment and sent to bidders on April 26, 1950, After an engineering review of these bids, it was necessary to reject the proposal of the lowest bidder and place an order with the second lowest bidder, the same vendor who had built the first increment of dehumidification units. The reasons for selection of this bidder were primarily his ability to deliver onthe required schedule and his ability to provide units which had many components interchangeable with the previous units eupplied. 5-258