Separate abstracts were prepared for 11 sections of this report.

From Abstract: "This document is a review of the principles, procedures, and instruments used in the measurement of visual range. The fundamental concepts of the visual range of the objects and lights are discussed. The principles of operation of the several classes of atmospheric attenuation meters are reviewed and representative instruments are described."

A general review, description, and history of geothermal development at the Geysers is presented. Particular emphasis is placed on environmental impacts of development of the area. The discussion is presented under the following chapter titles: introduction; energy, enthalpy and the First Law; vapor-producing geothermal reservoirs--review and models; geothermal; entropy and the Second Law; power plants--basics; H/sub 2/S emissions; hydrogen sulfide--possible health effects and odor; other emissions; power plant hydrogen sulfide abatement; hot water based geothermal development; phytotoxicity of geothermal emissions; appendices; and bibliography. (JGB)

The status of knowledge of attempts to utilize hot dry rock (HDR) geothermal energy is summarized. It contains (1) descriptions or case histories of the ERDA-funded projects at Marysville, MT, Fenton Hill, NM, and Coso Hot Springs, CA; (2) a review of the status of existing techniques available for exploration and delineation of HDR; (3) descriptions of other potential HDR sites; (4) definitions of the probable types of HDR resource localities; and (5) an estimate of the magnitude of the HDR resource base in the conterminous United States. The scope is limited to that part of HDR resource assessment related to the determination of the extent and character of HDR, with emphasis on the igneous-related type. It is estimated that approximately 74 Q (1 Q = 1,000 Quads) of heat is stored in these sites within the conterminous U.S. at depths less than 10 km and temperatures above 150/sup 0/C, the minimum for power generation. (Q = 10/sup 18/ BTU = 10/sup 21/J; the total U.S. consumption for 1972 was approximately 0.07 Q). Approximately 6300 Q are stored in the conduction-dominated parts of the crust in the western U.S. (23% of the total surface area), again at depths less than …

Separate abstracts were prepared for each of the 8 included sections. (MOW)