Color; 55 x 45 cm., on sheet 95 x 47 cm., folded to 24 x 10 cm. Panel title: Las Vegas city map. Copyright held by Cardinal Publishing Company. Relief shown by hachures. Includes illustrations and advertisements. Index, text, illustrations, advertisements, and map of "Lake Mead National Recreation Area, lower basin section" on verso. Original publisher: Cardinal Publishing Company.

Halsted advises on legal interpretations of use of force in guarding railroad property.

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."