Great Mill Rock, lying midway in Hell Gate, almost opposite the island-reef that has just been doomed to destruction, is supposed to have been the Rock on which the Corsair’s daughter was thrown when her father’s ship went down. The writer of these pages once knew a lady who, in her youth, lived with her parents on this same island, her father at that time being in the employ of the Government. This lady always seemed delighted when telling any one how she had often carried convicts, who had escaped from the prisons on Blackwell’s Island, in her skiff to the main-land. Of course, such little frolics happened when she was young, romantic, and—sympathetic. To make these feats of bravery appear more daring, they were accomplished late at night.
There were nearly four miles of tunneling under Flood Rock, or about 21,670 feet. The longest galleries were four blocks in length, or 1,200 feet. If these galleries had been in a straight line their distance would have been equal to a walk from the Battery to Forty-second street. Twenty-four galleries or tunnels were run from north to south, which were intersected by forty-six others, running nearly east and west. The tunnels were on an average ten feet from floor to ceiling and six or eight feet wide. The rock taken from them measured 80,000 cubic yards. There were 467 huge pillars supporting the roof. All through these galleries and corridors workmen had bored holes nine feet deep and three inches in diameter. The columns were also honey-combed with holes. There were 13,286 of such holes, which were filled with dynamite and powder cartridges. The chief engineer had only to touch an electric button to explode all this destructive compound. Had one of those unpleasant looking cartridges fallen from the hand of a workman upon the rocky floor, and exploded, it would have ignited all the rest, and thus caused a terrible disaster. Each cartridge weighed about six pounds. They resembled rolling-pins in size, and were delivered at Flood Rock by a tug-boat. They were received in square boxes, and, if they had been placed in a line, they would have reached twenty-two miles. The previous explosion at Hell Gate, directed by the same engineer, was effected with 50,000 pounds of rack-a-rock. During the charging of the mine at that time the workmen dropped three cartridges. We have heard of but one having been dropped at Flood Rock. Of course the greatest precaution was exercised to prevent a catastrophe. Twenty picked miners had charge of placing the cartridges in position. An elevator ran up and down the shaft bringing explosives to the men below. The cartridges were hoisted on cars and trundled away by mule power to the different corridors.
There was a weird, strange fascination about those dimly-lighted caverns, and the visitor often stopped to admire the marvellous effect of light on the great blocks of crystal quartz over which the clear water rippled in brightness and splendor. A wooden bridge spanned a deep ditch, which was so accurately laid out that it collected nearly all the water that found its way into the tunnels. The pumps disposed of this at the rate of 40,000 gallons per hour. The late explosion, it is asserted by those familiar with the subject, was the greatest ever known in the world. Now that the nine or ten acres of rock and island are blown up, dredging machines will clear the channel, and dump the stone into almost bottomless holes in the neighborhood. The mixing of such an immense quantity of powder so near the city was done on Little Mill Rock Island, under the careful supervision of Lieutenant Derby. The compound was mixed in a lead-lined tank by men who used wooden hoes. It was then poked from a trough into copper cylinders two and a half inches in diameter and two feet long, and pressed down solid with wooden rammers. Each cylinder when full was soldered so as to make it water-tight.
When compared to the great operations that have just terminated, those of the past seem like child’s play. Maillefort’s process of discharging cans filled with gunpowder was only useful in removing projecting points of rock. It was entirely inadequate to cope with flat areas of rock, and after three years—1851, 1852, and 1853—operations were suspended, with no great results, while the hungry reefs and boiling floods claimed their victims as before.
Though this work has cost much treasure, never was money better spent. The scene of this great undertaking lies in the collection district of New York, the nearest port of entry. The amount of revenue collected during the year 1884, was, in round numbers, over $135,000,000. The amount of commerce and navigation that will be benefitted by the completion of this work daily is estimated at millions of dollars.
The cry—so familiar to those who ply the waters of the Sound—“Look out for breakers!” will resound in this often-fatal locality no more—and Flood Rock, with all its obstructions, it is hoped, has disappeared forever beneath the green tide that swells through this once-turbulent Strait.
A Souvenir
OF THE
GREAT EXPLOSION.
WITH A
Historical Sketch of the Famous Strait
during the last 250 Years.