ABSTRACT
Saturday 10 October 1885 was a special day in New York City. A large crowd had gathered on the shore of the East River to witness an historic event, and many more spectators were in boats which formed a circle a mile in diameter. The centre of attention was Flood Rock, partly submerged and a notorious obstruction to shipping approaching New York. At 11.13 am, eleven-year-old Mary Newton depressed a button to send an electric current surging into banks of detonators, initiating the explosion of 42 000 pounds of dynamite and 240 000 pounds of an explosive called Rackarock1 which had been packed into subterranean tunnels in the rock. The water boiled and bubbled, spray shot 200 feet into the air and the rumbling explosion lasted for more than a minute, breaking a few windows locally and registering on seismographs at Harvard University, 200 miles away in Boston. The partly submerged Flood Rock was no more. Hell Gate, as the narrow channel around the rock was known, had been thrown open.
