Abstract: The records of formal cases relating to the regulation of dam construction on navigable rivers, of natural gas pipelines, and of the interstate transmission and distribution of electricity, in which the Commission appeared before the Federal Power Commission as an intervenor in behalf of the state or as a party to the case. Files include correspondence, applications, orders, briefs, reports, complaints, notices, petitions, decisions, statistical data, charts, maps, photographs, and transcripts of testimony.