1975

These two water turbines were probably the largest and nearly the most powerful ever built in the United States, supplying direct mechanical power to a manufacturing plant. Their installation between 1871 and 1873 makes them among the oldest surviving water turbines. A dam at Cohoes diverted water to mills and factories along a power canal system. The vertical-shaft turbines at the mill were said to run at 800 horsepower (600 kilowatt) under a head of 20 feet and were connected to an overhead shaft by bevel gearing.

The Saugus Ironworks, the first commercial ironworks in North America, was an impressive technological achievement for an early colony. The same basic processes are used today: reducing iron oxide with carbon to produce metallic iron that can be cast in a mold, producing wrought iron by puddling cast iron, and fabricating wrought iron with power hammer and rolls.

In the mid-1800s Virginia City was America's greatest producer of high-grade silver and gold ore. When mining activities began, natural springs provided water to the camps. As the population grew, the Virginia and Gold Hill Water Company was formed to address the need for more water. The company first drew water from tunnels that had been driven into the mountains by prospectors. Water was stored in wooden tanks and sent through pipes into the town. 

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.