Wernwag’s new bridge, built in 1812, was an elegant single-trussed arch spanning over 340 feet (102 meters)—certainly the longest of its kind in the United States and (according to some sources) the second-longest single-span bridge in the world at the time. The totally enclosed, elegant, low-arch bridge terminated in classical loggias at each end. Ten rectangular windows on each side provided light and ventilation for travelers. Graceful as it was, its achievement does not lie in its appearance but in the genius of its timber engineering. The wooden road deck was supported on five laminated arch beams that rose a little over 3 feet (1.07 meters) at midspan. On each side of the deck the river was spanned by a bow lattice beam, shallower at midpoint than at the ends and stiffened along its length with twenty-eight sets of double diagonal bracing. Iron tension ties anchored the beams to the ground at the masonry abutments, and others complemented the bracing along their entire length.

Wernwag’s reputation was established as a builder of long-span wooden truss bridges, and he built several more, including the Hickman Covered Bridge (1838) in central Kentucky. Also known locally as the Wernwag Bridge, it was the longest cantilever wooden bridge in the country. The practice of building wooden covered bridges spread quickly throughout the United States, and literally thousands were built during the nineteenth century. The Covered Bridge Society of America identifies over 1,500 extant covered bridges throughout the world. Over two-thirds of them are in North America. Pennsylvania has 219, over half of which are still in use on public roads.

Further reading

Allen, Richard Sanders. 1983. Covered Bridges of the Northeast. New York: Viking Penguin.

McKee, Brian J. 1997. Historic American Covered Bridges. New York: Oxford University Press.

Colossus of Rhodes


One of the seven wonders of the ancient world, the huge statue of the pre-Olympian sun god Helios stood at the entrance to the harbor of Rhodes on the Aegean island of the same name. The work of the celebrated sculptor Chares of Lindos, the giant figure, shown in some representations to be shielding his eyes as he looked out across the sea, towered 110 feet (33 meters) above the entrance to the Mandraki harbor. According to Greek mythology, Helios was the son of the Titans Hyperion and Thea, and brother of Selene, goddess of the moon, and Eos, goddess of the dawn. He was worshiped throughout the Peloponnese, and the people of Rhodes held annual gymnastic games in his honor.

The cast-bronze shell of the Colossus, reinforced and stabilized with an iron-and-stone framework, stood on a white marble base. It has been suggested that, in order to attach the upper parts of the monument, earth ramps and mounds were built. Work commenced around 294 b.c.—although some sources put the date at ten years earlier—and the statue took twelve years to complete. Its size is hard to comprehend, but some idea can be gained from Pliny the Elder, who wrote, “Few people can make their arms meet round the thumb.” From medieval times, artists’ romanticized impressions have shown the Colossus straddling the entrance to Mandraki harbor, towering over the ships that sailed between his feet. Given its height, the width of the harbor mouth, and the technology available to the builders, that construct is most improbable. The fact is that no one knows exactly what the statue looked like, nor where it stood. Recent scholarship suggests that it stood on the eastern promontory of the Mandraki, or perhaps a little inland.

Rhodes was an important island in the ancient civilization of the Aegean. The Dorians inhabited it in the second millennium b.c., and their city-states of Lindos, Camiros, and Ialysos were vigorous commercial centers with colonies throughout the region. In the fifth century b.c., it belonged to the Delian League, a confederacy of city-states led by Athens, ties they severed in 412 b.c. Just four years later their own confederation was celebrated in the completion of the new city of Rhodes, said to have been designed by Hippodamos of Miletus; it seems more likely that it was laid out according to Hippodamean principles.

In 332 b.c. Rhodes came under the control of Alexander the Great, but following his death nine