f our ingenious writers to give expression to his
thoughts in "Letters from under a Bridge." With an eye and an ear for
Nature's poetry, the gleam of lamps from a bridge, the figures that pass
and repass thereon, the rush and the lull of waters beneath, the
perspective of the arch, the weather-stains on the parapet, the sunshine
and the cloud-shadows around, are phases and sounds fraught with meaning
and mystery.

It is an acknowledged truth in the philosophy of Art, that Beauty is the
handmaid of Use; and as the grace of the swan and the horse results from
a conformation whose _rationale_ is movement, so the pillar that
supports the roof, and the arch that spans the current, by their
serviceable fitness, wed grace of form to wise utility. The laws of
architecture illustrate this principle copiously; but in no single and
familiar product of human skill is it more striking than in bridges; if
lightness, symmetry, elegance, proportion charm the ideal sense, not
less are the economy and adaptation of the structure impressive to the
eye of science. Perhaps the ideas of use and beauty, of convenience and
taste, in no instance, coalesce more obviously; and therefore, of all
human inventions, the bridge lends the most undisputed charm to the
landscape. It is one of those symbols of humanity which spring from and
are not grafted upon Nature; it proclaims her affinity with man, and
links her spontaneous benefits with his invention and his needs; it
seems to celebrate the stream over which it rises, and to wed the
wayward waters to the order and the mystery of life. There is no hint of
superfluity or impertinence in a bridge; it blends with the wildest and
the most cultivated scene with singular aptitude, and is a feature of
both rural and metropolitan landscape that strikes the mind as
essential. The most usual form has its counterpart in those rocky arches
which flood and fire have excavated or penned up in many picturesque
regions,--the segments of caverns, or the ribs of strata,--so that,
without the instinctive suggestion of the mind itself, Nature furnishes
complete models of a bridge whereon neither Art nor Science can improve.
Herein the most advanced and the most rude peoples own a common skill;
bridges, of some kind, and all adapted to their respective countries,
being the familiar invention of savage necessity and architectural
genius. The explorer finds them in Africa as well as the artist in Rome;
swung, like huge ha