Connecticut western news., 1876-09-22
The Great Explosion.

The great blast which is to remove the Instructions at He'll Gate, is announced for to day, CThursday,) and perhaps before this meets the eye of the readers will have oc- cured. Workmen have for several days past been busy loading the holes, which are 3,678 in number. The columns or sup porting pillars, numbering 172, are pierced from floor to roof with holes, and the roof also. The holes are arranged in groups of 20, and each one is filled with white pine plug, on the end of which is a piece of tin with it's number-from l to 2O-stamped upon it. All the plugs in group are con- nected with string, which passes from one to the other, thus preventing any confusion in separating group from group. Each group has its designating mark, and thus they are as easily referred to as are the blocks of houses in city.
 The cartridges were delivered at the gov ernment works by the contractors. packed ln boxes. They are in cans from 3-s to 3-S inches in diameter, ,and about 22 inches long, filled with explosive material. There are three classes of these cartridges of thlee different degrees of strength, and they are all packed in boxes foot square by 34 inches long. These boxes, when delivered at the government wharf, are handled in the most careful manner. The late acci- dent has caused the men to appreciate the power of the material they are handling. In the tunnels, where the work is done by means of the ordinary mining lamps, the same care is observable. A plug is with drawn and cartridge of the least explosive force inserted. This is pushed back to its place by means of long pole; anothee of higher power follows it, and then anoth- CT of still higher grade. after which the plug is returned to its place. The plugs will be taken out when all the holes have been thus filled, and small exploding car tridges of dynamite with Illuminating caps will take their place. The dynamite being the hardest to explode, is placed next the ! Illuminating mercury contained in the caps, which is the greatest detonator of all.
 All the exploding charges of a group will
 
 to another, which will take the place of the cord now connecting the plugs. The ends of this wire will be connected with the cleo tric batteries by two wires called ''ead wires." The battery will be placed in g bomb proof structure only short distance from the shaft. The circuit will be con nected, at the last minute, by General New ton in person. He, with his staff, will oc cupY position back of the battery on g high point of land, and the circuit will be closed by means of small battery and connecting wires at that place and i'll the following manner. He will send. by oper- ating his small battery, an electric spark to a small torpedo on the top of the bomb proof structure. When the torpedo ex. p!odes it will sever the string by which the plates of the battery inside the building art suspended. These plates falling into tho fluids, send other electrical currents alonf the wires which lead to the holes in tht mine below, causing the simultaneous ex plosion of the charges.
 The ledge of rock, of which Hallet's Point is the northeast end, crops out of thu ground at various places between there an( l the landing for the Harlem boats, passe under the East River ard makes its appear ance again upon the upper end of Black wells Island. Along this line the shocl will be the most severely felt. It is though that owing to the fact that the tunnels vii ! be filled with water previous to the exple } sion that the force of the shock will not b. 7 greatly felt, and aside from the breaking o few panes of glass there will be no dam age done.
 LATER.-On account of an unexpecte delay about getting the Vulcan powde needed at the Hell Gate excavations, th : explosion of the great blast is postpone till next Sunday.