Standing around this "well," the rumbling noises were more distinct than we had yet heard them, and were accompanied by a great splashing, and also by a hissing sound, as of escaping air or steam; and, on peering cautiously down into the hole, we could discern the water in motion.

The iceberg heaved slightly with the swell: the gurgling and hissing appeared to follow the heaving motion.
"I think there must be great cavities down in the ice, which serve as chambers for compressed air," remarked Raed; "and somehow the heaving of the berg acts as an air-pump,--something like an hydraulic ram, you know." As none of us could suggest any better explanation, we accepted this theory, though it was not very clear.
We were going back toward the crevice, when a loud gurgling roar, followed by a report like the discharge of a twenty-four-pounder, made the berg tremble; and, turning, we saw the water streaming from the well.

Another gurgle and another report succeeded, almost in the same instant.

Jets of water, and bits of ice, were spouted high into the air, and came down splashing and glancing about.

We made off as expeditiously as we could.