near the Zero Tower, and in general police and cle@n UP around all structures. Also during this week a % i ft. square concrete slab 4 inches thick was poured underneath the Zero Tower. This was the last concrete to be poured for any Am 5trUCtUre and all work up to this time was one week ahead of schedule. Hwever, there still remained four concrete bases to be poured for seismographinstruments;two located on this island, and two to be precast for Parry Island. This work was finished during the next week and Mr. Cloud of the U. S. Coast and Geodetic Survey, who arrived 24 March, began installationof the seismographequip-nt. The seismographinstallationswere ccmpleted on 31 March. SOM minor changes in plans of finished structureswere requested by Dr. Hartmann and Dr. Krause when they visited the island on 18 and 19 March. These changes are incorporatedin Change Order No. 4, Par la and lb, along with an additional requireamnt (par lc). For the latter, a salvaged 150 CU. ft. refrigeratorand a 175 CU”.ft. Navy pontoon cube were used, located south of the Tank Shelter, buried 4 ft. in the ground and backfilled on three sides and top so as to form a complete shelter~ This was a minor job completed Monday, 29 Harch. The ramps in front and I I I I I I rear of the Hartmann blast footings consisted of earth fill pushed into place by bulldozersand fini?h graded by hand. The ramps were then wet compacted and grouted over with a dxture of 1 part cant and 4 parts sand to a thickness averaging 1 inch. This job was fhished Friday, 26 March, and on Saturday, 2? lbrch, the east ditch alo~ the footings 46 Section XVI I I ‘1 I