Eleven of these assemblies were required. The J-Division letter of April 17 also stated that before procuring any of these assemblies prints of H & N drawings were to be forwarded to them for approval. This drawing was prepared, and prints were forwarded to J-Division on May 11, 1950. On June 25, 1950, at a meeting in Los Angeles, representatives of J- Division, NOL, and H & N diseussed in detail the NOBL program. The NOL representative had brought with him from Washington marked-up prints of H & N drawings which had been forwarded to NOBL by J-Division. H & N was instructed to correct its tracings and send prints directly to NOBL for approval, H& N was further instructed as follows: Stations 20 and 21 (Field Panels). Take bids on 16 assemblies, but Station 27 (Concrete Gauge Mounts). Take bids on 8 units, and pro- wait for approval of H & N drawings by NOBL before awarding a contract. cure same. Stations 28 and 29 (Instrument Posts). procure same, Stations and procure same. and Take bids on 50 units and Steel Stake Gauge Mounts). Station 36 (Gauge Mounting Plates). Take bids on 90 units Take bids on 11 units and pro-~ cure same, Also on June 28, 1950 H & N was furnished with NOBL sketches of Station 37a, b, c, (Pylon) and Station 37d, e, f (Ground Pylon Auxiliary) by NOL, and instructed by J-Division to prepare drawings and send prints to NOBL and J-Division for approval. were sent out on July 13, 1950. These drawings were prepared and prints The Pylon consisted of steel plates bolted on structural I-sections to form a steel tank 15 feet long by 15 feet high by 6 1/2 inches wide and constructed in five sections to facilitate transporting and handling in the Field, The center section contained four cylindrical steel chambers open on one end to receive steel closure plates similar to those used in the Field Panel assembly. In the field, the Pylon was set upright on a conerete pad and securely anchored thereto. The Ground Pylon Auxiliary consisted of a 14-inch diameter by 18-inch long steel chamber set vertically in a concrete block. The lower end was closed, and the upper end was open to receive a steel closure plate similar to those used on the Field Panel. Also on July 13, 1950 prints of the revised drawings for Stations 20, 21, 27, 28, 29, 33, 34, and 36 were sent to J-Division and NOBL for appro- val and to the H & N Construction Department for use in obtaining bids and procuring those items for which approval had been received. On July 19, 1950, in a telephone conversation with H& N, the J-Divi- sion representative stated that H & N drawings of the Field Panel 5-181