bank descends from the above-mentioned ledge to the beach; and to it the plants are almost limited. The slope itself is covered with loose fragments of rock, the debris of the cliff above, further broken up by frost, and ice-bound to a depth which there was no opportunity of ascertaining; for on the day the island was visited, the superficial masses alone were slightly loosened by the sun's rays. Thus the plants are confined to an almost incessantly frozen locality, and a particularly barren soil, liable to shift at every partial thaw. During nearly the entire year, even during the summer weeks which the Expedition spent in sight of Cockburn Island, it was constantly covered with snow. Fortunately the ships occupied a position that permitted of landing, on almost the only day when it was practicable to form a collection. The vegetation of so low a degree of latitude might be supposed to remain torpid, except for a few days in the year; when if the warmth were genial, and a short period of growing weather took place, the plants would receive an extraordinary stimulus. But far from such being the case, the effect of the sun's rays, when they momentarily appear, is only prejudicial to vegetation. The black and porous stones quickly part with their moisture; and the Lecanora and Ulva consequently become so crisp and parched, that they crumble into fragments when an attempt is made to remove them.
"The conducting power of the minerals in