Previously, under the Establishment, the local collectors of customs were in charge of the lighthouses and other aids to navigation. In time, all duties regarding aids to navigation were taken from them. The Board demanded that only those who could read were to be appointed as keepers in order that they be able to read their written instructions. These instructions were detailed and covered everything possible about the operation of lighthouses, leaving little discretion to the keeper. The Board struggled to eliminate politics from its activities, and slowly the organization became a professional career agency, helped greatly by the Civil Service Reform Acts of 1871 and 1883. Keepers became civil service employees in 1896. Most important, the Board was constantly mindful of advancing technology and took advantage of new types of lighthouses, buoys, or fog signals, as well as improvement in lighthouse optics. Over the next five decades several advances in lighthouse construction technology took place including the development of the exposed screwpile lighthouses, exoskeleton lighthouses, waveswept interlocking stone lighthouses, iron caisson lighthouses, and breakwater lighthouses.