Travel Reference
In-Depth Information
INTERESTING FACT:
Portland Head Light, which
is accessible by car, is the third oldest in the United
States. It was erected in 1791.
Prior to the mid 1800s, lighthouses were constructed of local stone or
wood. Around 1850 Congress directed the US Army Corps of Engineers to
standardize designs. This resulted in six basic shapes using stone, brick
or iron plates that can be seen today.
Placement and tower height was determined by a variety of factors, in-
cluding exposure to the sea during times of violent storms and visibility.
A light 50 feet above the sea can be seen from a distance of approximately
eight miles. To double that distance to 16 miles, the height of the tower
must increase by a factor of four.
To avoid confusion among mariners, the colors and flash pattern of light-
houses are varied. Charts reveal the frequency of the flash and note when
beacons may be blocked by shore-side obstacles.
The Fresnel Lens
In the early years lighthouses often burned sperm whale oil and
later kerosene to generate light. Eventually all were electrified.
Winslow Lewis' invention in 1810 of the Fresnel lens, which mag-
nifies and concentrates the light from the multiple lamps, made
lighthouses much more efficient. The beacons could be seen from
farther away and the amount of oil needed was reduced signifi-
cantly. Polished glass monstrosities standing up to 10 feet tall
and weighing thousands of pounds, each Fresnel lens is unique.
One of the finest collections of Fresnel lenses can be found on dis-
play at the Shore Village Lighthouse Museum in Rockland.
594-0311.
Directly offshore, from Rockland, some 25 miles out to be exact, is
Matinicus Light. First put into service in 1827, it was nearly destroyed by
a fierce winter storm in 1839. While all lighthouses have a rich and often
well-documented history, Matinicus Rock's is perhaps the most famous,
thanks to the heroic efforts of lighthouse keeper Samuel Burgess' 17-
year-old daughter Abbie.
