Removal of Hell Gate rocks
40°46′57″N 73°55′27″W / 40.7826°N 73.9241°W
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The removal of obstructive rocks from Hell Gate , a narrow tidal strait in New York City's East River and a major water transportation route, began in 1849, when French engineer Benjamin Maillefert, cleared some of the rocks. Then in 1851, the U.S. Army Corps of Engineers, led by General John Newton, began to do the job, in an operation which was to span 70 years.[1] On September 24, 1876, the Corps used 50,000 pounds (23,000 kg) of explosives to blast the rocks, which was followed by further blasting.[2] The process was started by excavating under Hallets reef from Astoria. Cornish miners, assisted by steam drills, dug galleries under the reef, which were then interconnected. They later drilled holes for explosives. A patent was issued for the detonating device. After the explosion, the rock debris was dredged and dropped into a deep part of the river. This was not repeated at the later Flood Rock explosion.
On October 10, 1885, the Corps carried out the largest explosion in this process, annihilating Flood Rock with 300,000 pounds (140,000 kg) of explosives.[3] The blast was felt as far away as Princeton, New Jersey (50 miles).[3] It sent a geyser of water 250 feet (76 m) in the air.[4] The blast has been described as "the largest planned explosion before testing began for the atomic bomb",[4] although the detonation at the Battle of Messines in 1917 was larger. Some of the rubble from the detonation was used in 1890 to fill the gap between Great Mill Rock and Little Mill Rock, merging the two islands into a single island, Mill Rock.[3]
Etymology
The name "Hell Gate" is a corruption of the Dutch phrase Hellegat (it first appeared on a Dutch map as Helle Gadt),[5] which could mean either "bright strait" or "clear opening",[6] and it was originally applied to the entirety of the East River. Dutch explorer Adriaen Block, the first European known to have navigated the strait, described it in his journals during his 1614 voyage aboard the Onrust. Hellegat is a fairly common name for waterways in the Low Countries, with at least 20 examples.[7] Because explorers found navigation hazardous in this New World place of rocks and converging tide-driven currents (from the Long Island Sound, Harlem River strait, Upper Bay of New York Harbor, and lesser channels, some of which have been filled), the Anglicization stuck.[8]
Timeline
- 1832: Pot Rock removed, cost $20,000 (equivalent to $610,000 in 2023), depth increased from 18.3 to 20.6 feet.
- 1871: Coenties Reef removed.
- 1872: Frying-pan Rock removed.
- 1869–1873: Diamond Reef removed.
- August 1869 – 1876: Reef at Hallett's Point removed.
- October 10, 1885: Flood Rock removed.
- 1890: Rubble from Flood Rock was used to fill the gap between Great Mill Rock and Little Mill Rock.
Initial efforts
The rocks, which impeded ship travel between the Atlantic Ocean and New York City via Long Island Sound, were off a Long Island headland known as Hallett's Point and extended into the East River toward Wards Island. The narrow channel was a danger to navigators since the area was first explored. Periodically, merchants and other interested parties would try to get something done about the problem. In 1832, the New York State legislature was presented with a petition for a canal to be built through Hallet's Point, thus avoiding Hell Gate altogether. Instead, the legislature responded by providing ships with pilots trained to navigate the shoals for the next 15 years.[9]
Removing the rocks was mentioned in an 1848 United States Navy report which recommended the destruction of Pot Rock, Frying Pan Rock, and Way's Reef; the first two were smaller, pointed rocks, and Way's Reef was a long ledge. The report also recommended that the middle channel be deepened for civilian use and military defense. Underwater blasting was in its infancy, and early technology was of limited use; cans of powder were placed against the side or top of a rock and detonated with a battery.
In 1849, Benjamin Maillefert, a French engineer whose specialty was underwater blasting, had cleared some of the rocks. Ebenezer Meriam had organized a subscription to pay Maillefert $6,000 to, for instance, reduce "Pot Rock" to provide 24 feet (7.3 m) of depth at low-mean water. While ships continued to run aground (in the 1850s about 2% of ships did so) and petitions continued to call for action, the federal government undertook surveys of the area which ended in 1851 with a detailed and accurate map.[9] By then Maillefert had cleared the rock "Baldheaded Billy", and it was reported that Pot Rock had been reduced to 20.5 feet (6.2 m), which encouraged the United States Congress to appropriate $20,000 for further clearing of the strait. However, a more accurate survey showed that the depth of Pot Rock was actually a little more than 18 feet (5.5 m), and eventually Congress withdrew its funding.[10]
With the main shipping channels into New York through the TVerrazano Narrows into New York Harbor silting up with sand due to littoral drift, thus providing ships with less depth, and a new generation of larger ships coming online – epitomized by Isambard Kingdom Brunel's SS Great Eastern, popularly known as "Leviathan" – New York began to be concerned that it would start to lose its status as a great port if a "back door" entrance into the harbor was not created.[11] In the 1850s the depth continued to lessen – the harbor commission said in 1850 that the mean water low was 24 feet (7.3 m) and the extreme water low was 23 feet (7.0 m) – while the draft required by the new ships continued to increase, meaning it was only safe for them to enter the harbor at high tide.[12]
The U.S. Congress, realizing that the problem needed to be addressed, appropriated $20,000 for the Army Corps of Engineers to continue Maillefert's work, but the money was soon spent without appreciable change in the hazards of navigating the strait. An advisory council recommended in 1856 that the strait be cleared of all obstacles, but nothing was done, and the Civil War soon broke out.[13]
After the Civil War
 | This section relies largely or entirely upon a single source. (September 2022) |
In the late 1860s, after the Civil War, Congress realized the military importance of having easily navigable waterways, and charged the Army Corps of Engineers with clearing Hell Gate of the rocks there that caused a danger to navigation. According to a January 1867 Army Corps of Engineers report, deepening the channel from 18.3 to 20.6 feet (5.6 to 6.3 m) would cost $18,000, about half the cost of the annual loss in shipping.
A steam-powered drilling scow, with a 32-foot (9.8 m) hole to accommodate 21 drills, was used to remove the rocks in the middle of the channel. It was first used on Diamond Reef in the spring of 1869; a number of holes were drilled into the rock, into which 30-to-35-pound (14 to 16 kg) charges of nitroglycerin were inserted. Coenties Reef followed in 1871 with 17 surface blasts, and 39 surface blasts two years later; it was broken up with 17,127 pounds (7,769 kg) of nitroglycerin. Congress failed to include Diamond Reef in its 1875 appropriation, and debris removal was suspended. The scow was towed to Frying Pan Rock in 1872, where 11 surface blasts were made.
Removal of the Hallett's Point reef began in August 1869. A wood cofferdam was fastened to the rocks, and the water was pumped out about to accommodate a shaft; work was then suspended because its funding had run out. The work resumed in July 1870, and the shaft was sunk to 33 feet (10 m) below mean low water. The rock was hand-drilled that year, with 8,306 cubic yards (6,350 m3) removed. Steam-powered equipment was added the following year, speeding up the work. The number of feet of tunnel driven during the year was 1,653, and of transverse galleries 653.75. The quantity of rock removed was 8,293 cubic yards. A ground-plan of the work herewith gives an excellent idea of the excavation as completed. An exceedingly well-executed model of the works was exhibited at the Centennial Exhibition at Philadelphia. It is made exactly to scale, and well represents the nature and extent of the vast operations that have now been successfully completed.
The rock-bed of the river is, in the model, raised from the pillars that support it, so that a close inspection of the interior may be made. There are one hundred and seventy-two of these pillars, pierced with about four thousand drill-holes; and the shell, or roof, or bed of the river, varies from six to sixteen feet in thickness. No less than thirty thousand cubic yards of broken stone was left under water, all of which was removed by dredging.
A detailed survey of the upper surface of the reef was made in 1871, by Mr. William Preass, assisted by Mr. F. Sylvester. They took more than sixteen thousand soundings, each separately located, by means of instruments, from the shore. Great pains were taken to delineate exactly the surface of the rocks. The appropriation of 1871 was two hundred and twenty-five thousand dollars, — just one-half the amount asked for by Gen. Newton, who regretted that the beginning of operations on the Gridiron was thus prevented, as he considered this rock more dangerous to the navigation of large vessels than Hallett's-Point Reef. For the next year he asked six hundred thousand dollars, but got less than half that sum. About the middle of November 1873, work was suspended for want of funds; at the end of the fiscal year, June 30, 1874, it was found, that, for the four months and a half during which operations had been carried on, 896 linear feet of tunnels had been opened, and 4,648 cubic yards of rock removed. The total length of tunnels and galleries then amounted to 6,780.67 feet. The excavation now being nearly finished, the manner of finally blowing up the whole mine began to exercise the minds of the engineers. Gen. Newton finally suggested his own plan for blowing up the reef at Hallett's Point, which was to perforate each pier with drill-holes entirely or partly through its mass, a sufficient number of these being provided to complete the destruction of the pier when fully charged. The charges in the different holes of the same pier were to be connected together; and a fuse, composed of a quick explosive, would connect the system of charges in each pier with those of the neighboring piers. By this mode, the communication of heat or the electric spark to a few centres of explosion would suffice to propagate it through the whole system, because the explosion of the connecting fuse would advance more rapidly than the demolition of the rock. Gen. Newton's plan was adopted, with few slight changes, principally suggested by himself. Instead of depending on explosives to convey fire from pier to pier throughout the mine, an electric spark was sent directly to every centre, insuring the simultaneous explosion of the whole mine. It was decided that the minimum amount of explosives could be determined by placing one charge in each square pier and two in each oblong pier; but this mode would make the lines of least resistance the maximum, and thus increase the shock, which would be propagated through the reef to the dwellings upon the land. It was therefore determined to decrease the lines of least resistance, which would multiply the number of blasts, and increase the quantity of explosives, but would, at the same time, reduce to a minimum the vibrating influence through the reef. It was, therefore, calculated that the exterior effect, except an agitation of water, would be small.
The proximity of the reef to habitations at Astoria, Ward's Island, and Blackwell's Island, made it necessary to devise a system of explosion, which, effecting the work of demolition would, at the same time, do no damage to life and property.
The atmosphere and the rock being the mediums through which the shock would be transmitted, it was essential that the waves propagated through these should be made as small as possible.
It was evident, in the first place, that, if to each charge its full capacity of useful work in the breaking-up of the rock were assigned, regard being likewise had to the superincumbent weight of water, no external effect of moment would be perceived in the atmosphere.
In the second place, it was evident that the magnitude of the rock-wave would depend greatly upon the amount contained in individual charges; that is, if eighty pounds were required for the individual charge, the vibration of the rock would be much greater than if these charges did not exceed twenty pounds. It was known that eighty-pound charges of nitroglycerine, fired in numbers of twelve to twenty, did not cause a destructive wave.
Again: the reef, after excavation, being connected with the rest of the rock formation only through the piers and the outer edge of the roof, it was inferred that the shock propagated in the rock should be estimated as due mainly to the charges necessary to disrupt the piers and roof from their connection with the bed-rock; and, also, that the additional number of charges required to break up the roof and piers would not enter largely into the amount of shock transmitted under ground.
These were the fundamental ideas upon which the system of mines was established. As the tunnels in radial lines concentrated upon the land, an accumulative explosive effect in that direction was prevented by so proportioning the charges that the roof should be broken through by the first impulse in many places, and thus give vent upward.
To prevent a concentric explosion, by which the debris might be heaped up in large masses near the centre of the area, the charges in the outer zone of the semi-elliptical reef were increased beyond those of the other portions; and by this means the masses of debris fell generally back in the places to which they originally belonged. Some portions were thrown beyond the limits of the reef toward the channel, and constituted what may be termed a dispersive explosion.
Hallett's-point Reef is in the shape of an irregular semi-ellipse; the major axis, which lies next to the shore, being seven hundred and seventy feet in length, and the minor axis projecting straight into the channel about three hundred feet. The cubic contents above the depth of twenty-six feet at mean low water amount to fifty-one thousand yards. Besides the risk of striking the reef, it produces eddies on both sides of it according to the direction of the tidal currents, and is much in the way of vessels coming down in the ebb in the effort to hug the shore, and thus avoid being drawn upon Middle Reef. The explosives used in tunnelling at Hallett's Point have been nitroglycerine and its compounds, and gunpowder; the' latter being used only when the rock was weak and seamy. Nitroglycerine was always used for driving the headings of the tunnels. To drive a heading, the drill-holes are made at an angle with the fuse, so that the charge lifts out the rock by its explosion. A cavity being made in the middle of the heading, holes are drilled around it, and the surrounding rock blown into it. Only one blast is exploded at a time, as great care has to be taken not to shake the structure overhead by too heavy vibrations. There is consequently no volley firing, and the galvanic battery is not used for discharging the blasts. The average twelve months' work, with six Burleigh drills, was the excavation of two hundred and thirty-five lineal feet of heading per month. Up to June 1872, the work had been prosecuted by hand-drilling, with the exception of 20,160 lineal feet of drilling by the Burleigh drill, and 7,000 feet by the diamond drill. That by the Burleigh drills was done by contract, at so much a foot; and the diamond drill, purchased for the purpose of exploring the rock ahead, was put in competition with it.
The cost of drilling, after a long trial with the Burleigh, is found to be between thirty-six and thirty-seven cents per foot, including repairs, etc. The cost of hammer-drilling was found to be about ninety-five cents per foot. The number of feet of holes drilled by each machine per shift of eight hours was thirty feet.
The diamond drill, owing to the encounter of frequent veins of pure quartz in the rock, often gives out, and has to be repaired. Owing to the restricted area of the tunnels and galleries, the work of excavation was almost exclusively that denominated heading, without the advantage of enlargement. The rock, after being blasted, was lifted by hand into a box resting on a truck-car, which was run down to a point upon a rail-track, and thence drawn by a mule to the shaft, where the box was hoisted by a derrick, and its contents emptied into dump-cars, to be rolled away, and deposited in the pile. Calling the cost of blasting and removing one cubic yard one dollar, the following gives the proportion of each item of expenditure:
| Blasting | .4600 |
| Transporting rock to shaft | .1700 |
| Hoisting | .0328 |
| Dumping | .0203 |
| Pumping | .1037 |
| Incidental | .2132 |
The work of excavation having been finished, the drills were set to work perforating the roof and piers with holes to receive the final charges which are to explode the mine.
The mode of calculating and arranging the charges was to consider the roof-holes as the receptacles of explosives enough to form common mines.
The line of least resistance was assumed as the distance from mid-length of the charge to the surface of the rock. Since the charges were perfectly tamped by the confined water within the excavation, this rule of measuring the line of least resistance was assumed to be practically correct. With less perfect tamping, the lines of least resistance for such mines designed to break through the roof would have required estimates quite different.
The average amount of explosives required to break up and dislodge one cubic yard in enlargement had already been found to be .97 pound; and from this resulted
L being line of least resistance in feet.
All roof-holes, excepting those over piers, were treated by this formula. The piers, being very irregular in shape and size, would have exacted much care and time to have located the holes and proportioned the charges to the exact mathematical requirements in each case. One pound and a half of explosives were assigned, as a rule, to each cubic yard of the piers; it being considered of the first importance to demolish completely these supports of the roof.
The roof-holes above piers were charged from the formula:
being successively .038, .05, and .06, increasing from the shaft outward.
The bodies of piers within the outer zone were charged with two pounds per cubic yard. Within the inner zone, where the depth was comparatively little, it was considered proper to reduce the charges to the smallest limit capable of affording a good result, both to avoid disturbance of the atmosphere and to prevent a concentrated action, due to the direction of the tunnel upon the land. The increased proportion given to the charges within the outer zone favored this intention, by giving quick vent to the gases in that direction.
The cubic contents of the roof and piers were 63,135 yards and the amount of explosives as follows: rend-rock 9,127 ½ lbs., vulcan powder 11,852 13/16 lbs., dynamite 28,935 ¼ lbs. — total 49,915 9/16 lbs. Being at the rate of 0.79 pound to each cubic yard.
The explosives were packed at the respective places of manufacture, in tin cartridge-cases, the last being furnished by the Government.
The number of holes charged was 4,427, and the number of tins used was 13,596; eighty-seven percent being twenty-two inches, and the remainder eleven inches, in length.
The holes being tapering, the cases varied in diameter from one and three-eighths to two and a half inches; the intermediate sizes differing by one-eighth of an inch.
One end of the tin case was fitted with a screw cap, with rubber washers to exclude water; the other end being arranged with four short lengths of brass wire, soldered on the perimeter of the bottom, and spread out. When the cartridge was pushed home, the wires, by their elasticity, pressing against the side of the hole, prevented a falling-out.
On September 11 the charging of holes was commenced, and finished at nine p.m. on the 20th, — consuming nine days. Had the cartridges been delivered in good condition, this operation would have consumed only about four days.
These holes were made from two to three inches in diameter, and from six to ten feet apart, and their average depth about nine feet. The size of the holes, and their direction and distances apart, were made to vary according to the character of the rock to be broken. The drilling of these holes up into the roof of the mine soon increased the leakage of water into the works from three hundred gallons per minute to five hundred, it being impossible to avoid tapping a seam occasionally. Many of the holes that were found to be leaking were plugged up temporarily, and the leakage thus reduced. The outside gallery and the No. 4 heading were deepened so as to concentrate all the leakage, and cause it to flow to the shaft-end of that heading, where pumps were placed. The following shows the amount of the appropriations made by Congress each year for Hell-gate and East-river improvement, and the whole amount expended up to the date of the last report of Gen. Newton to the chief engineer:
| 1868 | $85,000 |
| 1869 | 180,000 |
| 1870 | 250,000 |
| 1871 | 225,000 |
| 1872 | 225,000 |
| 1873 | 225,000 |
| 1874 | 250,000 |
| 1875 | 250,000 |
| Total | $1,690,000 |
After this report was made, Congress appropriated $250,000.
| Total amount of appropriations | $1,940,000.00 |
| Total amount expended to August 1, 1876 | $1,686,811.45 |
| Estimated cost of completing entire work of improving Hell Gate and the East River | $5,139,120.00 |
Care had been taken to test the various kinds of explosives. Up to the middle of 1874, nitroglycerine had been principally used for blasting purposes. Several hundred pounds of mica-powder were then tried, some giant-powder, several thousand pounds of rend-rock, and, later, considerable vulcan-powder was used. All of these are nitroglycerine compounds. Neither of them was found to be as powerful as the glycerine itself; but it was repeatedly demonstrated, that, with ten ounces of rend-rock or vulcan-powder, they could break as much rock as they formerly did with eight ounces of nitroglycerine, while the cost per pound was less than one-half that of glycerine.
The Mode of Firing (Final Explosion 1876)
After the holes had been charged with tin canisters, the next operation was to insert the priming-charges, which were contained in brass tubes. Brass was preferred to tin on account of greater durability in salt water and better protection against leakage, — conditions insuring the detonations at least against moisture, should the exposure be of long duration.
The amount of these charges — three-fourths of a pound to each primer — has been included in the grand total already given. The primers contained also, as detonators, fuses holding each twenty grains of fulminate of mercury. The terminals of two connecting-wires were inserted in each fuse, and bridged with .001-inch silver platinum wires a quarter inch in length.
The fuses, in groups of twenty, were connected in continuous series with connecting-wires. A lead and a return wire were attached to each group.
Twenty primers, with fuses and wires properly arranged in a box, with lead and return wires on reels, were carried to each party engaged in this work. The time consumed in placing 3,680 primers, unreeling the lead and return wires, and leading these out of the shaft, was two days and a fraction.
The connecting-wires, in length varying in the different groups from twenty to thirty-five feet, were copper wires of No. 18 American gauge (.04303 inch), insulated by a coat of guttapercha; the size after coating being No. 9 American gauge (.11443 inch). The total amount used was 118,525 feet.
The lead and return wires were copper wires of No. 12 American gauge (.080808 inch), insulated with two coats of guttapercha; size of coating. No. 4 American gauge (.2043 inch). The total amount used was 147,703 feet, in lengths from 250 to 625 feet.
The batteries used consisted respectively of forty, forty-three, and forty-four cells of zinc and carbon, or nine hundred and sixty cells in all, divided into twenty-three distinct batteries, each battery to fire a hundred and sixty fuses, arranged in divided circuit, in eight groups of twenty each. The fluid was made in the proportion of six pounds of bichromate of potassa, one gallon concentrated pure English sulphuric acid, and three gallons of water.
The separate batteries were so arranged in two frames, that all the cells could be immersed by the same operation. The system then consisted of 3,680 mines and twenty-three batteries; each battery assigned to a hundred and sixty mines, which were divided into eight groups of twenty each.
The mines of each group were connected in continuous series, and a lead and return wire to the battery closed the circuit. To insure the simultaneous discharge of the whole system, a "circuit-closer" was introduced.
The method, which will be explained, for one division of a hundred and sixty charges, will suffice for the others.
One lead-wire from each group of the division — i.e., eight in all — was connected with one pole of the battery. The other pole was then connected with a brass pin, penetrating through a wooden horizontal disc, which, being let go by the run, would cause the brass pin to enter a cup filled with mercury, planted in a second wooden horizontal disc fixed in position. If the eight return-wires of the same group were then connected with the brass cup containing mercury, it is evident, that, when the brass pin entered the mercury-cup, the circuit would be closed, and explosion would result. Obviously, if, instead of one pin and one mercury-cup, twenty-three pins and twenty-three cups were attached respectively to the two discs, and the same connections as just described made for each and every division of a hundred and sixty mines, a simultaneous explosion would result at the moment when the upper disc should fall upon the lower.
The upper disc was held over the lower one, and apart from it, by a cord passing and looped over the tin case of a torpedo, securely attached to a frame. This torpedo, or cartridge of dynamite, was provided with a detonator, from which two wires passed to a small battery situated twenty-one hundred feet distant. The torpedo was fired by closing this circuit with a Morse's key : the cord being severed, allowed the upper disc to descend upon the lower, and thus close the circuit of the great batteries.
The siphon was started at 12.07 a.m. on September 23, and at 7.30 p.m. the excavations were filled to the level of the tide.
The mines were fired at three seconds past 2.50 p.m., on September 24, 1876.
The explosion was distinguished by the absence of hurtful shock in the atmosphere, in the water, or under ground.
The elevation of spray, vapor, and gases, projected upward, reached to the height of a hundred and twenty-three feet, measured at the centre and highest point. The quantity of water actually raised was trifling, as evidenced by the almost total absence of a propagated wave. The explosive effort in the air was not perceptible; the glass in buildings close to the dam, and of one in particular along the shore-line of the shaft itself, not having in a single instance been broken.
The underground shock was trifling, but perceptibly felt in the cities of New York and Brooklyn. Along the line of the reef, a little plastering was dislodged from a ceiling in a house a hundred and fifty yards, and in two houses six thousand yards, from the work.
The new facts obtained by this experience were:
- 1st, that an unlimited amount of explosives, distributed in blast-holes in moderate charges, proportioned to the work to be done, thoroughly confined in the rock, and tamped with water, may be fired without damage to surrounding objects.
- 2nd, that an unlimited number of mines may be simultaneously fired by passing electric currents through the platinum-wire bridges of detonators.
The total cubic contents demolished by the explosion were 63,135 cubic yards solid. On the different suppositions for the broken debris of once and a half, and of twice, the original volume, there would result respectively 94,702.5 and 126,370 cubic yards.
The contractor was set at work removing the broken rock with a steam-grapple. The cost to the government is $2.40 per ton of 2,240 pounds.
The quantity of broken stone to be grappled in order to obtain a depth of twenty-eight feet was 45,488 cubic yards.[14]
See also
References
Notes
- ^ "NOAA 200th Collections: Hell Gate and Its Approaches nautical chart from 1851". National Oceanic and Atmospheric Administration. Retrieved April 12, 2009.
- ^ "Rendering Hell-Gate Rocks; The Submarine Mine Exploded". The New York Times. September 25, 1876. p. 1. Retrieved November 19, 2011.
- ^ a b c "Mill Rock Island". New York City Department of Parks and Recreation. June 6, 2001. Retrieved April 12, 2009.
- ^ a b Whitt, Toni (June 2, 2006). "The East River is Cleaner Now. The Water Birds Say So". The New York Times. Retrieved April 12, 2009.
- ^ "Dutch Place Names: Plaatsnamenl" Library of Congress: The Atlantic World
- ^ Gannett, Henry (1905). The Origin of Certain Place Names in the United States. Govt. Print. Off. p. 154.
- ^ Van Dyck, Vic. "Hellegat en Hellegat" (in Dutch). Retrieved November 19, 2011.
- ^ "Hell Gate". New York History. Retrieved April 15, 2012.
- ^ a b Eldredge & Horenstein, p.93
- ^ Steinberg, pp.99–100
- ^ Steinberg, pp.105–106
- ^ Eldredge & Horenstein (2014), pp.94–95
- ^ Eldredge & Horenstein (2014), p.95
- ^ Eissler, Manuel (1889). The modern high explosives : Nitro-glycerine and dynamite: their manufacture, their use, and their application to mining and military engineering; pyroxyline, or gun-cotton; the fulminates, picrates, and chlorates. Also the chemistry and analysis of the elementary bodies which enter into the manufacture of the principal nitro-compounds. New York: J. Wiley. pp. 344–357. Retrieved September 9, 2022.
Bibliography
- Eissler, M. (1884). The Modern High Explosives: Nitro-glycerine and Dynamite: Their Manufacture, Their Use, and Their Application to Mining and Military Engineering; Pyroxyline, Or Gun-cotton; the Fulminates, Picrates, and Chlorates. Also the Chemistry and Analysis of the Elementary Bodies which Enter Into the Manufacture of the Principal Nitro-compounds. J. Wiley. pp. 344—357.
- Eldredge, Niles and Horenstein, Sidney (2014). Concrete Jungle: New York City and Our Last Best Hope for a Sustainable Future. Berkeley, California: University of California Press. ISBN 978-0-520-27015-2.
- Steinberg, Ted (2010). Gotham Unbound: The Ecological History of Greater New York. New York: Simon & Schuster. ISBN 978-1-476-74124-6.
