ESL, Niveau avancé
From the time men were capable of gliding over the water, some form of lighthouses were constructed to warn sailors of ......... danger. At first, huge bonfires were built to guide the ships, later man-made structures were erected.
Early records credit Egyptians with being the first people to erect a lighthouse to guide ships away from rocks or ......... shores. It stood 900 feet tall and endured 1500 years of foul weather.
In 1822, a French inventor, Augustin Fesnel, had an ......... moment in his workroom when noticing how far light traveled through a prism. He deduced that the range of light emitted in lighthouses might be increased by using large glass prisms.
Fesnel experimented for a number of years until receiving funds to put his theory into practice. In 1841, he demonstrated how the prisms ......... light, increasing the distance the warning could be seen by sailors.
The first lighthouse built in the United States was the Boston Lighthouse on Brewster Island in 1716. Although, destroyed in the Revolutionary War, the ......... of the colonists was responsible for three more lighthouses being built.
George Washington, the first president of the United States, believed that the ......... of the country depended on good trading conditions. He wanted more lighthouses built to protect ships from jagged reefs and dangerous shores.
President Washington's ......... agreed, and the "Lighthouse Bill" was passed, making the construction and upkeep of lighthouses a federal responsibility.
The Auditor of the Treasury, Stephan Pleasanton, was given the job of ......... funds for the lighthouses. Unfortunately, he was so determined to spend as little money as possible, many of them were structurally inferior to withstanding adverse weather conditions.
Since so many of the lighthouses had become structural ........., a board of investigation convened to solve some of the problems. A lighthouse board was elected, made up of men with military and engineering experience.
In later years, the responsibility for lighthouses was given to the U.S. Coast Guard. Due to electrification, solar power, and automation, the structures were most ........., with only periodic maintenance required.