the structure being covered with soil to a level with the roof on the two sides and back, The front side had four openings; two were 2 foot 5 inches by 6 inches, and two were 1 foot 3 inches by 8 inches, Two 6 inch diameter pipe vents were set in the roof. Four steel shelves 12 inches wide were fastened to the walls by brackets, The drawings were completed on November 1, 1950 and approved on November 28, 1950. cate 623 was given on February 27, 1950. Approval to relo- Stations 621, 623a, and 624a - Muzin - NRDL. Fastened to a wing wall of military structures 3.3.4 and 3.3.3, were a series of incendiary test panels, The User did all of the design work required. 621 was originally on Military Structure 3.1.1; however a letter from AEC moved it to 3.3.3 on October 14, 1950. On December 19, 1950 it was deleted from the program entirely by the AEC. Stations 623b and 624b - Muzin; Stations 625b and c - Kirinian; Sta- tions 626b and c —- NRDL. These stations were camera mounts and were the same as Station 302e; therefore no new drawings were required. The sta- tion description and locations were furnished by AEC on October 14, 1950. Additional information on location was given by J-Division on October 27, 1950. Stations 6311 through 6 -_Engebi - BRL/APG, The User furnished all of the parts of these stations except for the power outlets that were needed. 6321 was relocated on December 8, 1950; 6341, 6342, and 6321 were relocated December 13; and 6321, 6322 on January 5, 1951 by the AEC Resident Engineer. Station 771 - Engebi; Station 772 - The Aomon Group; Station 773 Runit; and Station 774 - Bogombogo - USC & GS AFOAT. On April 17, 1950 J-Division furnished H & N with sketches and design data for this group of buildings to house seismographs. The structure consisted of two com partments, one being the seismograph room and the other an entrance well. The entrance well was 5 feet 6 inches square and 7 feet three inches deep with a cover made up of two hinged doors. The seismograph room was 6 feet square and 6 feet 6 inches deep, the entrance into the room being through a standard 2 foot 2 inch by 5 foot 6 inch blast door located in the common wall between this room and the well. The seismograph room had a coral sand floor. The instrument was mounted on a block of concrete 5 feet square and as deep as was necessary to bond it securely to the underlying coral bedrock, The whole structure was streamlined using a coral fill covering so as to minimize the building vibration due to the air shock. All of the walls and roof of this structure were 12 inch reinforced concrete, except for Station 774, which was 1 foot 4 inches. The drawings were approved, except for minor pipe changes, on June 28, 1950, by the User. On October 9, 1950, the AEC deleted 774. Station 775 - Eniwetok - USC & GS AFOAT, This building served the same purpose as 771, However, due to its extreme distance from the expe- riment islands, the construction was wood frame and wood sheathed inside and outside, The sketches and design data were furnished by J-Division on April 24, 1950. The interior dimensions were 6 feet 3 inches square by 6 feet 10 inches high. The building was placed above ground, and no S°1TT