The sensation we experienced was certainly very disagreeable and painful, and for a pleasure trip I certainly would not recommend any one to undertake the journey. Should a lady go down, however strong-minded she might be, I would not answer for the consequences. One of the party was so much affected by the pressure of the air that our conductor had to turn off the cock frequently. The stranger’s ears pained him greatly, and blood began to spurt from them. Having reached the bottom of the caisson, where the workmen were digging out the earth and blasting rock, we were detained in the lock some minutes, to allow the admission of air of the same density as that below. This being done, I descended a short iron ladder leading into the bottom of the caisson, and speedily found myself standing on the bed of the river, seventy-eight feet below water-mark. There were several men working in their shirt sleeves, with big drops of perspiration rolling off their cheeks. The subterranean vault was very well lighted with gas forced down the pipes in the same manner as the air; and it is a curious fact, that in the compressed air a foot burner gives as much light as a four foot one would in the ordinary atmosphere. The caisson seemed to be full of steam, as if a hundred washerwomen were plying their avocation at the tub. The bottom of the caisson is divided into several chambers by means of iron and wood partitions, with entrances leading into each other. The air does not seem impure nor unpleasant. According to an examination made a few days before my visit, it was then found to contain a small percentage of carbonic acid, but not enough to do any harm. [Sidenote: OPERATIONS BELOW.] As soon as the sand is dug, it is sent up various pipes, four inches in diameter, which operate in the same way as siphons. It is odd to notice with what force the sand ascends to the top of the caisson, and it is all that six men can do to shovel it in fast enough. Boulders of trap rock were found embedded in the quicksand. These were broken up and hoisted out by an apparatus similar to a dredging machine, working in an immense shaft filled with water. The shape of the interior of the caisson resembles very much the lips of an enormous bell, and in reality it is worked upon the same principle as an ordinary diving-bell, the water being kept out by the great pressure of air. As soon as the caisson is perfectly settled, and all the sand and debris down to the bed rock is removed, the interior is filled with concrete and masonry, and thus the pier obtains a foundation perfectly solid.