By 1847, the United States Congress became serious about reforming the Lighthouse Establishment which had been in existence since 1791 and in response to a number of complaints, the U.S. Congress removed the responsibility for the construction of six new light stations from the U.S. Treasury Department's Fifth Auditor (Stephen Pleasonton), and transferred it to the supervision of the United States Army's, long-time construction agency, the Corps of Engineers. When it became clear that this would not alleviate the underlying problems in the Lighthouse Establishment, Congress then felt compelled to deal the final blow to Pleasanton's administration. The ensuing congressional investigation took more than four years to effect a change in the administration of navigation aids along the American coasts. During that time, congressional appointee, Lt. Jenkins of the U.S. Coast Survey conducted interviews with pilots and mariners, engaged in domestic and foreign research, and was involved in a number of hearings into existing navigational aids administration.