USA

Edison's simple and unprecedented instrument allowed for the first time the permanent recording and reproduction of sound, especially the human voice. On December 6, 1877, Edison put tinfoil around the cylinder, turned the handle of the shaft and, shouting into one of the diaphragms, recorded a verse of Mary Had a Little Lamb "almost perfectly." From this machine evolved the phonographs and record industries of the world.

This dynamo, connected directly to a high-speed steam engine, was one of six that produced direct current at Thomas A. Edison's electric power station at 257 Pearl Street in New York City. The Pearl Street Station was the prototype for central station power generation. Edison set out in 1878 to provide an electrical distribution system to bring lighting into the home: His first filament lamp lit on October 21, 1879. With the help of Frances Upton and C.L. Clarke, Edison built his engine-driven dynamo for the 1881 Paris Electrical Exposition.

Operated by the Philadelphia Electric Company (PECO), now known as Exelon Corp., Eddystone Station Unit #1 is a 325 MW pulverized-coal-fired plant that pushed the technology of steam-electric generating plants. When built in 1960, engineers sought to make a more efficient plant using higher temperatures and pressures and larger machines. Previous experience at Philo 6 (Zanesville, Ohio, 1957) had demonstrated supercritical steam plants would work, so engineers pushed beyond that frontier to even larger machines and efficiencies.

In the decade following the Civil War, the Mississippi River began to lose its standing as the primary transport artery in the Midwest. Railroads were taking over, and Chicago was rapidly becoming the center of Midwestern commerce. The Eads Bridge was the first major railroad link over the Mississippi, constructed by the city of St. Louis in an attempt to maintain its dominance as a regional commercial hub.

The Durango-Silverton Narrow Gauge Branch of the Denver & Rio Grande Western Railroad extends from the town of Durango to the mining camp of Silverton. Built in 1882 through one of the most rugged mountain areas of the nation, its complexity remains a testament to the role civil engineering played in the development of the western United States. 

The tracks rise up the sheer, steep Animas Canyon, running along a rock ledge just wide enough to carry the train. The line is used today as a tourist attraction, carrying visitors through the picturesque San Juan Mountains.

Designed by Sam Diescher, son-in-law of the Monongahela's designer John Endres, the Duquesne Incline opened May 20, 1877, as the second of seventeen built and operated in the Pittsburgh area. It has operated with only minor interruptions for the last one hundred years. A preservation group from Duquesne Heights and Mount Washington interceded in 1962 to refurbish this incline to working order. Like the Monongahela, the Duquesne was steam powered and then converted to electric and updated with modern safety devices.

Not only was Dunlap's Creek Bridge the first cast-iron bridge in America, it was the first metal bridge anywhere to use what its builder, Capt. Richard Delafield, U.S. Army Corps of Engineers, described as "standardized, interchangeable, manufactured parts." The bridge was built as part of the federal government's effort to make repairs on the National Road  before handing authority over to the states. Dunlap's Creek at Brownsville was an especially troublesome crossing, having destroyed three previous bridges since 1801.

The significance of the 15-mile Whitewater Canal was not in its ability to create a profit, but rather its effect on the economic growth of the Whitewater River Valley, considered the gateway to the interior of Indiana. Before the canal, travel was challenging. Most waterways in Indiana were only navigable by canoe, and the alternative - horse and wagon - was difficult, slow and expensive.  

Like other American cities in the late 19th century, Baltimore had grown so quickly its supply system was unable to provide city residents with a dependable supply of water. Two reservoirs built outside the city helped increase capacity, but heavy rainfalls in the largely agricultural area tended to foul this additional water supply. City officials elected to construct a holding reservoir within the city - contained by an earthen dam - where silty water would be allowed to settle. No such project had ever been undertaken in the United States.

The drilling of this oil well marks the modern phase of the petroleum industry. A series of revolutionary technological changes, unforeseen even by the most prophetic, followed. Drake demonstrated practical oil recovery by applying salt-well drilling techniques, including the use of the derrick, and invented the modern method of driving iron pipe.