Oruktor Amphibolos

History

In late 1804 the Philadelphia Board of Health hired Oliver Evans, a local inventor who had built one of the first high-pressure steam engines in the United States, to make a machine for clearing mud and debris from the city's docks ^[1][5]. A Pennsylvania law of March 15, 1805, paid for the work with a charge of four cents per ton on ships leaving for foreign ports ^[1]. Evans called the machine Oruktor Amphibolos, from the Greek for amphibious digger ^[1].

Work began in the spring of 1805, and Evans advertised a public showing for July ^[1]. The hull had to travel from his shop to the river, so he set it on four wheels driven by its own engine. The first wheels reportedly collapsed under the weight and were replaced ^[5]. In Evans's own account, the machine went up Market Street and around Centre Square, site of the city waterworks, then entered the Schuylkill River and paddled down to the Delaware and back up to the city ^[1]. Wikipedia dates the street run to July 13, 1805 ^[5].

Design

The Oruktor was a flat-bottomed scow about 30 ft (9 m) long and 12 ft (3.7 m) wide, fitted with a chain of buckets to lift mud and hooks to pull out sticks and stones ^[1]. Evans gave its weight as 34,437 lb (15.6 t), usually quoted as about 17 tons, although some writers say 15 tons ^[1][4]. A small high-pressure steam engine with a 5 in (13 cm) cylinder and a 19 in (48 cm) stroke worked the dredging gear, and a paddle wheel at the stern moved it through the water ^[1]. Historian Steven Lubar estimates the engine's output at about 5 hp (3.7 kW) ^[1].

How strong is the claim to be first?

The Oruktor is often described as the first amphibious vehicle and the first self-propelled road vehicle in the United States ^[4][5]. The evidence for both claims is thin. No newspaper report of the demonstration is known, and the only mention from 1805, in Joseph Scott's gazetteer, may have been written before the machine ran ^[1]. John F. Watson, writing around 1840, remembered a machine that broke down and stood for months at Ninth and High streets ^[1][4]. Evans's later descriptions added speed, distance and crowds that his earlier ones lacked ^[1].

Lubar argues that a 5 hp engine with an improvised drive was unlikely to move such a heavy hull far on land, and he doubts the Oruktor deserves the titles of America's first steamboat, locomotive or car ^[1]. Wikipedia likewise calls the land trip improbable and the river trip unverified ^[5]. What can be said with confidence is that Evans built a steam dredge in 1805 that was meant to move on both land and water. How far it actually traveled under its own power is unknown ^[1][5].

Fate and legacy

The Board of Health spent about $4,000 on the project. According to Lubar, it sold the machine for parts in June 1809 for $31.10 ^[1]. Other accounts say it was scrapped in 1808 ^[5]. No original drawings of the machine are known, so pictures of it are later reconstructions ^[5].

The Oruktor remains a symbol of early American invention. A mural by Allyn Cox in the U.S. Capitol shows Evans's steam-powered amphibious dredging scow entering the Schuylkill and dates the scene to 1804 ^[2]. A print in the collections of The Henry Ford also uses the 1804 date ^[3]. Philadelphia marked the 200th anniversary of the machine on July 16, 2005 ^[1].

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