"Both sledges, however, succeeded in gaining the shore, and were drawn up off the beach, though not without great difficulty. Scarcely had they reached it, when that part of the ice from which they had just escaped burst asunder, and the water, rushing up from beneath, instantly precipitated it into the ocean. In a moment, as if by a signal, the whole mass of ice for several miles along the coast, and extending as far as the eye could reach, began to break up, and to be overwhelmed by the waves. The spectacle was awfully grand. The immense fields of ice rising out of the ocean clashing against each other, and then plunging into the deep with a violence which no language can describe, and with a noise like the discharge of a thousand cannon, was a sight which must have filled the most unreflecting mind with feelings of solemnity. "The Brethren were overwhelmed with amazement at their miraculous escape, and even the Esquimaux expressed gratitude to God for their deliverance." Such is the terrible aspect in which field-ice is seen when broken up and converted into smaller masses or _floes_. When these lie closely together the mass is called _pack-ice_; in which shape it usually drifts away with the southern currents, and, separating as it travels south, is met with in loose floating masses, of every fantastic form. There is always, as we have said, a large quantity of floe and pack-ice in the polar seas, which becomes incorporated with the new ice of the succeeding winter; and not infrequently whale and discovery ships get frozen into the pack, and remain there as firmly embedded as if they lay high and dry on land. When the pack is thus re-frozen, it usually remains stationary; but there are occasions and circumstances in which the entire body of a pack drifts slowly southward even during the whole year; showing clearly that oceanic circulation is by no means arrested by the icy hand of the hyperborean winter. A very remarkable drift of this kind is recorded by Captain McClintock of the _Fox_, which is worthy of being noticed here, as illustrative of the subject we are now considering and also as showing in a remarkable manner the awful dangers to which navigators may be exposed by the disruption of the pack in spring, and the wonderful, almost miraculous, manner in which they are delivered from imminent destruction.