Cabin John Aqueduct, designed by Montgomery C. Meigs, conveys drinking water from Great Falls, Maryland to Washington, D.C. It was the longest stone masonry arch in the world for nearly 40 years. The segmental arch of the bridge has a span of 220 feet and a rise of only 57 feet. The main arch ring is built of cut and dressed granite. The secondary arch ring is radially-laid sandstone, of which the rest of the bridge is also constructed.
1860-1869
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Image Credit: Public Domain (Author's Choice)Image Caption: Cabin John AqueductEra_date_from: 1864
1972
A product of the Northern California Gold Rush, the Bridgeport Covered Bridge is believed to be the longest, single-span, wooden covered bridge in the United States. Crossing the south fork of the Yuba River at a span of 233 feet, the bridge was built by the Virginia City Turnpike Company as part of a 14-mile toll road authorized by the California state legislature. The toll road was an essential link connecting Virginia City, Nevada, and the silver-producing Comstock Lode with the centers of California commerce.
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Image Credit: Courtesy Flickr/Rick Cooper (CC BY 2.0)Image Caption: The Bridgeport Covered Bridge, one of the longest covered bridges in the nationEra_date_from: 1862
1970
People thought inventor Walter Aiken was crazy when he proposed a railway to the top of Mt. Washington. Aiken built a model of the roadbed and track with a cog rail system, but entrepreneur Sylvester Marsh is credited for launching the Cog Railway and bringing Aiken's ideas to fruition.
In 1858 Marsh applied to the New Hampshire Legislature for a charter to build and operate the steam railway and was granted permission in 1859. Legend has it that an amendment was added offering permission to extend the railway to the moon.
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Image Credit: Courtesy Flickr/Dennis Jarvis (CC BY-SA 2.0)Image Caption: Mount Washington Cog RailwayEra_date_from: 1869
1975
Bread is considered a basic foodstuff; eaten down through the ages, it continues to be a staple of the modern diet. The development of baking powder made baking easier, quicker and more reliable for bakers in the mid-19th century. Eben Horsford’s unique formula was an important innovation and made the making of biscuits, cookies and other quick baking products simpler than before.
The commemorative plaques read:
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Image Credit: Courtesy Wikicommons/Lou Sander (CC BY-SA 3.0)Image Caption: In 2006 Rumford Baking Powder was designated a National Historic Chemical Landmark in recognition of its significance for making baking easier, quicker, and more reliable. Ingredients are monocalcium phosphate, sodium bicarbonate, and cornstarch.
2006
Innovations
