Rensselaer Union, Volume 9, Number 1, Rensselaer, Jasper County, 21 September 1876 — The Coming Explosion at Hell Gate. [ARTICLE]

The Coming Explosion at Hell Gate.

Gen. Newton has recently stated that the great explosion at Hell Gate will take place during the latter part of September. The excavations have been complete for some time past, but delays in passing the appropriation bill by Congress checked further operation, and for this reason the blow-up aid not occur on the 4th of July, as for a long period was contemplated. Those who expect to witness a gigantic column hurled hundreds of feet into the air, or look forward with some trepidation to the effects of fearful concussion on adjacent buildings, will hardly find their anticipations realized. The mine will he flooded previous to the explosion; and with the possible exception of jets forced through seams in the rocks, there is no reason to believe that any very remarkable exhibition of the tremendous force of the explosives will be manifest. From a scientific point of view the occasion will be of considerable interest, as the earth in the vicinity will be shaken by the communicated vibrations, which are likely to travel over a long distance. An opportunity will thus be afforded for measuring the velocity of sound waves through earth, and preparations are being made by scientific men to observe the same at points at distances 200 mid 800 miles away. The arrangements to guard against any possible danger are being perfected, ip utter disregard of the desires both of those who hope to see the great blast, and those who aspire to profit pecuniarly through the popular curiosity. Steamboats and other craft will be warned away, so that a view from the river will be out of the question; the authorities have Been requested not to grant passes to would-be spectators onWard’s Island, the best point of observation; and a bluff of earth and the buildings near the works prevent seeing the operations from the rear, so that the expectant populace will probably have to satisfy themselves with a distant view from the high land on the Hew York shore. How mnch powder, etc., will be burnt is not yet definitely stated. An approximate idea of the quantity may be gathered from the fact that there are about 4,000 drill holes, each three inches in diameter, and vaiying from seven to thirteen feet in depth. Each will be charged with a separate canister of dynamite, vulcan and rend-rock powder, and the simultaneous explosion will he effected by the current from a battery of 800 cells. About two pounds of powder are used to one of dyfcamite, and the charges are inserted in the 172 piers of rock and in the roof supported thereby. It is estimated that 30,000 cubic feet of broken rock will be left under water, and this will have to be removed by dredging, so as to secure a channel twenty-six feet in depth. The total length of tunnels, galleries, etc., excavated, is 7,425.67 feet. The amount thus far expended is $1,686,841.45. — Scientific American.