A lighthouse of the nineteenth century is a high cylinder of masonry,
surmounted by scientifically constructed machinery for throwing light.
The Caskets lighthouse in particular is a triple white tower, bearing
three light-rooms. These three chambers revolve on clockwork wheels,
with such precision that the man on watch who sees them from sea can
invariably take ten steps during their irradiation, and twenty-five
during their eclipse. Everything is based on the focal plan, and on the
rotation of the octagon drum, formed of eight wide simple lenses in
range, having above and below it two series of dioptric rings; an
algebraic gear, secured from the effects of the beating of winds and
waves by glass a millimetre thick[6], yet sometimes broken by the
sea-eagles, which dash themselves like great moths against these
gigantic lanterns. The building which encloses and sustains this
mechanism, and in which it is set, is also mathematically constructed.
Everything about it is plain, exact, bare, precise, correct. A
lighthouse is a mathematical figure.

In the seventeenth century a lighthouse was a sort of plume of the land
on the seashore. The architecture of a lighthouse tower was magnificent
and extravagant. It was covered with balconies, balusters, lodges,
alcoves, weathercocks. Nothing but masks, statues, foliage, volutes,
reliefs, figures large and small, medallions with inscriptions. _Pax in
bello_, said the Eddystone lighthouse. We may as well observe, by the
way, that this declaration of peace did not always disarm the ocean.
Winstanley repeated it on a lighthouse which he constructed at his own
expense, on a wild spot near Plymouth. The tower being finished, he shut
himself up in it to have it tried by the tempest. The storm came, and
carried off the lighthouse and Winstanley in it. Such excessive
adornment gave too great a hold to the hurricane, as generals too
brilliantly equipped in battle draw the enemy's fire. Besides whimsical