But to return—to cut into so hard a rock the contractors have to adopt the process of blasting, which is carried on upon a magnitude which has never been equalled. To penetrate the rocks sets of workmen, in twos, are employed in different parts of the face of the mountain, and these men drive a heading or gallery into the solid rock, about five feet high and three wide, for a distance of 30 to 40 feet, which is accomplished chiefly by blasting. In the extremity of this gallery, which runs first horizontally, and is then sunk perpendicularly, the powder is placed in a wood-case or bag, and the hole being tamped or filled up with clay, it is fired by the galvanic battery. The charges vary from one to five tons of gunpowder, according to the face of the rock to be acted upon; and the quantities thrown down varies from six to thirty thousand tons in an explosion. One of these “headings” or “shots” as they are called, went off this day (Dec. 7, 1852). Sir Richard Bulkeley, Bart., the Rev. J. Williams, M. Errington Stanley, Esq., and G. F. Lyster, Esq., were present on the occasion, and took their station on a bridge to witness the “shot;” but on seeing the stones roll through the air, they deemed it prudent to act upon the well known maxim, “retreat is the better part of valour,” and instantly left their elevated position, and placed themselves beneath the abutment of the bridge. The writer, who was present, was a little amused to see such a fine illustration of the first law of nature—SELF PRESERVATION. As a proof of the fearful extent of these explosions, I would just observe, that although the bridge on which the aforesaid gentlemen stood was about 800 yards from the quarry, a stone fell within a few yards of it. The effect of these blastings on the rock are sometimes of a curious character, but generally speaking the rock when thrown down leaves the surface of the cliff smooth and perpendicular. The stones thrown out are generally large, many of them weighing twenty tons. Shafts are also sunk from 30 to 40 feet deep. The quantity of stone taken from the quarries is accurately weighed, and already about two million tons have been buried in the sea. During the past year the average deposit has amounted to 3,500 tons per day, and supposing that there have been 250 full working days, this would give a deposit for the year of 875,000 tons.