（1）Origin of Aids to Navigation（Background of the Lighthouse）

Several thousand years ago，mankind contemplated going out to the sea by means of vessels．
It may be easily imagined that the top of high mountains，the head of capes，particular large trees，and outstanding natural spots served as targets to reach the point of destination．
However, with the increase in size，vessels began to travel at night．going further from the shore．
Thus, it became necessary to construct structures which could be recognized at night and from a far distance to replace existing landmarks． Fire was burned on capes and islands as well as on the top of high structures so that the fire and smoke could serve to guide navigating vessels．
This practice was the beginning of the modern lighthouse.
According to past records，at the port of Alexandria in Egypt at its height of prosperity in 279 B．C.,　a large lighthouse　of marble stone was constructed on the east end of the island of Pharos at the mouth of the port.（see page 34）
According to old records，there are also several lighthouses built by the 17th century with a chapel and living quarters for the holy staff light signals were provided by burning torches and grass on the roof of the structures as they were not equipped with lighting facilities such as the lens and reflecting apparatus．
The Cornna Lighthouse built on the east side of the Strait of Gibraltar in 1595 is the first lighthouse to be built for the sole purpose to serve as a lighthouse．
A small structure of 9 feet in height, a glass lantern was installed，and oil was burned inside the lantern．
Lighthouses in the early days were primitive structures，using wood and coal as the light source, gradually burning oil and candle light．
The invention of the lens contributed to increase the light power，and the availability of electric supply as the power source in lighthouses easily produced strong lights of several million candelas．

（ 1 candela＝approximately 1 candela power）