After the Civil War, the East River remained a massive unsolved problem for New York City. A major waterway into and out of New York Harbor--where customs revenue equaled 42 percent of the U.S. Government's income--the river's many hindrances, centered around Hell Gate, included whirlpools, rocks and reefs. These, combined with swirling currents and powerful tides, led to deaths, cargo losses and destruction of vessels. Charged with clearing the river, General John Newton of the Army Corps of Engineers went to work with the most rudimentary tools for diving, mining, lighting, pumping and drilling. For 20 years, his crews worked up and down the river, using a steam-drilling scow of his own design and a new and perilous explosive--nitroglycerine. In 1885, Newton destroyed the nine-acre Flood Rock with 282,730 pounds of high explosives. The demolition was watched by tens of thousands. This book chronicles the clearing of the East River and the ingenuity of the Army engineer whose work was praised by the National Academy of Sciences.