Evening journal., 1906-11-12

Another lighthouse Of similar eonstruc-
tion is that which stands upon Spectacle
Reef. In Lake Huron. near the Straits OF
Mackinac. There difficulties were not
tides nor waves. but Ice which in thou
sands Of acres and two feet or more In
thickness moves under the influence Of
currents at several miles an hour, and
exerts almost irresistible strength
The site Is upon a limestone reef i05h
miles from the nearest land and 10 miles
from scammons Harbor, where the stone.
which the structure stands Is II feet be-
meath the surface, the principal difficulty
lay, as at Minots Ledge, In the preparing
Of the foundation.
This was overcome by a pier Of protec-
ton inclosing a cofferdam. The crib, a
great box "a feet high and 90 feet square.
divided into compartments for ballast and
leaving an open space As feet square in
the center, was built In Scammons har-
Dor and towed to the site, where with
stones and gravel. II was sunk around
the rock. The top OF the compartment
thus formed a platform 70 feet above the
water.
Then the cofferdam was made. This
was a bottomless tub with slaves each
IA feet long, inches thick and inches
wide, held In place by three iron bands
inside and out. A loosely twisted rope
OF oakum, one and one-half inches in
diameter, was then tackled on the lower
edge Of the slaves and the tub was then
lowered. The bed rock was Irregular on
Its surface, In some places the difference
In vertical height being three feet, but
by carefully driving the slaves they took
up the Irregularities to a great extent
Then, between the outside Of the coffer
dam and the crib a four-lnch rope OF hay
and canvas was fastened at the bottom,
and as the pumps cleared the cofferdam
the pressure of water forced the canvas
against the slaves and the inside war
practically watertight.
The foundation stones, which had al
ready been prepared and cut to at one
into the other, were lowered and cement
ed. This required much time, and winter
was upon them just after the first few
stones were laid and work had TO be
abandoned. The wisdom OF the crib was
shown and the following summer the
structure was In fairly good shape. 50
that by the end Of the warm weather the
tower was well up.
The work on the tower was started Il
May, 1870. and the light was first lighted
on the finished structure In June, 1874
but as the actual working time was but
about 20 months, II Is considered thN
the structure was well and quickly erect
ed. 1t cost $4,000. The plans for the
light were prepared by Gen. o. NJ. Poe
and they have since been used for other
similar lights on the lakes.
Another type OF lighthouse. known as
the spider" and Of which those on the
reefs Of Florida are splendid examples
has become popular Of late years as the
skill In ironwork construction has ad.
yancec. The lighthouses on Fowey Rocks
and Alligator Reef stand guard over the
treacherous Florida Reefs. They are miles
from shore and are exposed 10 the full
sweep Of the Atlantic. which Is only
broken by the reefs a few hundred feet
away. but the great seas frequently throw
clouds Of spray as high as the lanterns,
over 100 feet above the water.
These lights were erected with much
difficulty, and It required about three
years for each, much Of the time being
lost on account or storms. and they cost
about $4,000 apiece. AS the structures
rest upon live coral rock a dozen feet
beneath the surface, the plans called f0I
the driving OF SIX great iron piles 10 feet
into the rock. The piles, together with
the entire superstructures, were built and
set up and fitted in the North and then
shipped 70 the nearest point on the main.
land, whence they we're carried out 70
The contractors FIRST built worki...
platform on the reef by driving a series
was rendered exceedingly difficult on ac
count OF sudden storms, and every few
days they were driven away. Despite ths
danger the brave spirits never hagged
and at last the platform was completed
and the work OF driving the great wrought
Iron piles began. II was painfully SLOW
and tedious as they bad to go down per
fectly straight. and every few minutes the
operations were suspended to make the
elaborate tests
Under the blistering snn. suspended
bet~iXt water and sky. with death always
nenr, the work was pushed as rapidly ~
possible and yet u was - months he
Tore the foundation vas pronounced dn
ishcd.
A. Il usually the case. the erection o.
he superstructure wne compr rriivciy easy
Each piece OF iron dtted nnd with boil,
ahd rlyets Il was placed togo ser bid hJ
bit until the end. when TIE lamp Wai
lighted and another beacon shed us vel
come rays across the Atlantic. such
were the experiences OF the builders OF
the Fowey Rock light, and, indeed, such
were the experiences OF those who erected
the Alligator Reef light.
Is II any wonder then that the light
house builder Is proud OF his work.
THOMAS WILSON.