'Philadelphia. Published by Charles Desilver.' 'Entered according to Act of Congress in the year 1856 by Charles Desilver in the Clerks office of the District Court of the Eastern District of Pennsylvania.' 'Engraved by J.L. Hazzard & E. Yeager.' Includes notes and insets titled 'Gold region of California' and 'District of Columbia.' Relief shown by hachures and spot heights. Also shows battle fields and proposed western railroad routes. Prime meridians: Washington and Greenwich. Atlas p. numbers in upper margin: 5-6. Scale 1:8,750,000 (W 126°--W 65°/N 48°--N 24°).

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.

From the Howard Cannon Photograph Collection (PH-00192). Stamped on verso: "Official Air Force Photo - Base Photo Branch - Holloman AFB, New Mexico"

Photographs from the University of Nevada, Las Vegas Creative Services Records (2010s) (PH-00388-05).