Guard, it is possible that Pleasonton continued to rely on Lewis's lamps instead of adopting Fresnel lenses at least partially due to the nature of the existing lighthouses. Evidence exists that with the Earth's curvature, the Fresnel lenses would have proved no better than Lewis's paraboloid lamps due to the low height of the lighthouse towers themselves and would not be able to be seen at much greater distances. In the end, it was Pleasonton's refusal to consider Fresnel's system that proved his downfall. This, coupled with his support for Lewis' outdated methods, led to further investigations by Congress; eventually, the United States Lighthouse Board was formed to remove Pleasonton's influence from the system altogether. Death Pleasonton was 78 years old when he died on January 31, 1855. He is buried in Congressional Cemetery. Legacy Pleasonton's appointment marked a turning point for the Lighthouse Establishment; responsibility for lighthouses had previously shifted from department to department, with no semblance of continuity. His administration lasted until 1852, at which point the United States Lighthouse Board was created; this was the longest period of stability the Lighthouse Establishment had seen up until that point. Still, many historians have criticized Pleasonton's administration, holding that his frugal nature and willingness to cut costs wherever possible did great harm to the Lighthouse Establishment's credibility. References External links 1770s births 1855 deaths Lighthouses in the United States United States Department of the Treasury officials Burials at the Congressional Cemetery