Transcribed from press release attached to back of photo: "PENETRATES EARTH 16,000 FEET A surface approaching the hardness of the diamond is applied by a new atomic-hydrogen welding process to the teeth of a rock bit drill at the Hughes Tool Company plant in Houston, Texas, owned by Howard Hughes, noted aircraft designer-flyer. The first Hughes rock bit revolutionized oil drilling practices in this nation several decades ago, making possible recovery of oil beneath hard rock formations at great depths. Most recent models have penetrated the earth below 16,000 feet. Hughes drills are used in 50 foreign countries. NOTE: The atomic-hydrogen process differs from other arc-welding processes in that the arc is formed between two electrodes, rather than one electrode and the work." The patent on the atomic-hydrogen process was awarded October 29, 1929.

Boulder City Museum basement floor plan.

The exterior of Hughes Research Laboratories where rock bits were test-drilled in Culver City, California in the 1940s. Transcribed from note taped to back of photo: "Rock bits are test-drilled in the laboratory under conditions that duplicate, as far as is possible in the laboratory, those encountered in actual drilling. As a result, rotational speeds, loads, and fluid volume are closely controlled. The rig operator occupies a splash-proof booth above the 'cellar floor.' The instruments on his control panel provide for application and measurement of variable axial loading on the drilling bit up to 100,000 lbs., variable rotational speeds up to 400 rpm, measurement of bit penetration over a total vertical travel of 5 feet at rates up to 180 ft. per hour, and torque. On the panel, also, are several controls for the operation of mud pump and other accessory equipment."

Hughes Helicopters Division of Summa Corporation in Culver City, California.