It will be remembered that the blast was exploded Oct. 10 at 11.13 o'clock, and a few seconds over. Prof. Rogers first observed disturbances in the mercury surface at 11.17.30, and from that time disturbance waves came at nearly regular intervals of about 18 seconds, until the maximum was reached on the fourth or fifth wave. Then the impulses declined in force and died away about as they had come. In addition to the screen Prof. Rogers made use of direct observation of the mercury surface through a microscope, thus giving him the added advantage of judging the wave's length, etc. which a direct view of them would furnish. Read more
On 10 October 1885 in New York City, the U.S. Army Corps of Engineers detonated 300,000 pounds of explosives on Flood Rock, annihilating the island, in order to clear the Hell Gate for the benefit of East River shipping traffic. The explosion sent a geyser of water 250 feet in the air; the blast was felt as far away as Princeton, New Jersey Read more