funnel shaped, was the result, necessitating the use of a cartridge, whose diameter must not exceed that of the smallest, which in this case was the lowest part of the drilled hole. The irregularity, and jagged edge of these unreamed holes, had also to be guarded against, lest the friction of any Nitro-Glycerin moistening the outside of the cartridge, might cause a casualty. I therefore determined, until better drilling could be secured, to use 2¼ inch two-ply rubber hose for cartridges, a material by no means desirable, because it afforded a cushion between the rock and the blast, but it became a necessity from the funnel shaped drill holes, when providing against the risk of premature explosion. The holes being 4½ inches in diameter at the upper part, and barely 3 inches at the bottom; the cartridge made of rubber hose, being uniform throughout, containing a column of liquid Nitro-Glycerin, 2¼ inches in diameter only, and 6 feet long; at the upper part of the holes there was an intervening cushion of water and hose, over 1 inch thick; and at the lower part, a cushion of ⅜ inch of hose. This should have been avoided, and I have mentioned these details as a caution to future operators, who desire the full explosive force of Nitro-Glycerin. The depth of water at or during high-tide, is about twenty-two feet, and at low tide, fourteen to fifteen feet, the tide running four miles an hour with an amount of silty matter, drainage of N. Y. City sewerage, rendering it impossible for a diver to distinguish objects one foot from his helmet. Under these circumstances plugs have to be inserted in the several holes, each plug attached to the other by a rope, so as to enable the diver to guide himself from one hole to the other. Owing to various interfering circumstances the holes were only ready for blasting on the 16th of December, 1870; and the second day after arrival in New York, accompanied with three assistants, I proceeded to the work; there was a stiff wind blowing from the northwest, which, meeting the tide, caused a chopping sea; the weather was cold as shown by the crust of ice attached to the scow. The frozen Nitro-Glycerin was thawed out by hot water obtained from the steam boiler on board the scow.