may be placed in the alleys or underground,
leaving the streets beautiful by day and glorified at night by the
torches of advanced civilization.

XIII

LIGHTHOUSES

At the present time thousands of lighthouses, light-ships, and
light-buoys guide the navigator along the waterways and into harbors and
warn him of dangerous shoals. Many wonderful feats of engineering are
involved in their construction and in no field of artificial lighting
has more ingenuity been displayed in devising powerful beams of light.
Many of these beacons of safety are automatic in operation and require
little attention. It has been said that nothing indicates the
liberality, prosperity, or intelligence of a nation more clearly than
the facilities which it affords for the safe approach of the mariner to
its shores. Surely these marine lights are important factors in modern
navigation.

The first "lighthouses" were beacon-fires of burning wood maintained by
priests for the benefit of the early commerce in the eastern part of the
Mediterranean Sea. As early as the seventh century before Christ these
beacon-fires were mentioned in writings. In the third century before the
Christian era a tower said to be of a great height was built on a small
island near Alexandria during the reign of Ptolemy II. The tower was
named Pharos, which is the origin of the term "pharology" applied to the
science of lighthouse construction. Caesar, who visited Alexandria two
centuries later, described the Pharos as a "tower of great height, of
wonderful construction." Fire was kept burning in it night and day and
Pliny said of it, "During the night it appears as bright as a star, and
during the day it is distinguished by the smoke." Apparently this tower
served as a lighthouse for more than a thousand years. It was found in
ruins in 1349. Throughout succeeding centuries many towers were built,
but little attention was given to the development of light-sources and
optical apparatus.

The first lighthouse in the United States and perhaps on the Western
continents was the Boston Light, which was completed in 1716. A few days
after it was put into operation a news item in a Boston paper heralded
the noteworthy event as follows:

By virtue of an Act of Assembly made in the First Year of His
Majesty's Reign, For Building and Maintaining a Light House
upon the Great Brewster (called Beacon-Island) at the Entrance
of the Harbour of Boston, in ord