d a half, the upper extremities being
left standing about five feet above the surface of the sands. For the
purpose of fixing the screws, a stage or raft of timber, thirty feet
square, was floated over the spot, with a capstan in the centre, which
was made to fit on the top of the iron shaft, and firmly keyed to it.
A power of about thirty men was employed for driving the screws, and
their labours were continued until their united force could scarcely
turn the capstan. This stage or raft, which had been formed in two
thicknesses crossing each other at right angles, and bolted at their
intersection, was, as a precautionary measure, allowed to remain. It
covered the whole site within the piles, and also extended some
distance beyond them. A curb about eighteen inches high was raised
round this stage; on its surface was arranged a quantity of brushwood,
and then about two hundred tons of rough stone, which sunk the stage
into the sand and prevented it from being displaced. Between the
spaces of the stage and the brushwood the sand was allowed to wash its
way, and it soon filled the interstices of the stone. The whole mass
soon became embedded below the surface of the sand, and gave
considerable lateral support to the piles, and formed a solid body for
the water to wash upon.

In this state the whole was allowed to remain for about two years,
during which time every change in the surface of the sand was
observed, and although early in the year 1839 violent storms occurred,
yet the screw-piles stood firmly, and the sand at no time was lowered
more than three feet. In August 1840 the raft was found to have
completely settled down, the piles were as firm as if they had been
screwed into clay; a lighthouse was therefore erected within the short
space of three months; and on the 16th February, 1841, a dioptric
fixed light was exhibited off this dangerous spot, and was visible ten
miles off in all directions.

But while the preparatory steps for this lighthouse were being taken,
a screw-pile lighthouse was begun and completed at Port Fleetwood on
the Wyre, near Lancaster; which being the first of the kind ever
constructed, deserves particular notice.

The preparatory stages were of a similar nature to those already
described. The foundation was formed of seven screw-piles, six
occupying the angles of a hexagon forty-six feet in diameter, and the
seventh being placed in the centre. From each screw proceeded a pile
fifteen feet