built, which was
launched like a ship, towed out to the reef and there grounded. When it
was pumped out the men worked inside with the water surrounding them
twelve to fourteen feet above their heads. Twenty months of work, or three
years in time, were occupied in erecting this light. Once in the spring,
when the keepers returned after the closed season to prepare for the
summer's navigation, they found the ice piled thirty feet against the
tower, and seventy feet above the doorway, so that they were compelled, in
order to enter the lighthouse, to cut through a huge iceberg of which it
was the core.

The Spectacle Reef light, like that at Minot's Ledge, is a simple tower of
massive masonry, and this is the approved design for lighthouses exposed
to very heavy strain from waves or ice. A simpler structure, used in
tranquil bays and in the less turbulent waters of the Gulf, is the
"screw-pile" lighthouse, built upon a skeleton framework of iron piling,
the piles having been so designed that they bore into the bed of the ocean
like augers on being turned. The "bug-light" in Boston Harbor, and the
light at the entrance to Hampton Roads are familiar instances of this sort
of construction. For all their apparent lightness of construction, they
are stout and seaworthy, and in their erection the builders have often had
to overcome obstacles and perils offered by the sea scarcely less savage
than those overcome at Minot's Ledge. Indeed, a lighthouse standing in its
strength, perhaps rising out of a placid summer sea, or towering from a
crest of rock which it seems incredible the sea should have ever swept,
gives little hint to the casual observer of the struggle that brave and
skilful men had to go through with before it could be erected. The light
at Tillamook Rock, near the mouth of the Columbia River, offers a striking
illustration of this. It is no slender shaft rising from a tumultuous sea,
but a spacious dwelling from which springs a square tower supporting the
light, the whole perched on the crest of a small rock rising precipitously
from the sea to the height of some forty feet. Yet, sturdy and secure as
the lighthouse now looks, its erection was one of the hardest tasks that
the board ever undertook. So steep are the sides of Tillamook Rock that to
land upon it, even in calm weather, is perilous, and the foreman of the
first party that went to prepare the ground for the light was drowned in
the attempt. Only after repea