After all, however, the advance upon the Pole itself, however interesting to the general public, is far less important to science than other objects which Arctic travellers have had in view. The inquiry into the phenomena of terrestrial magnetism within the Arctic regions; the investigation of oceanic movements there; of the laws according to which low temperatures are related to latitude and geographical conditions; the study of aerial phenomena; of the limits of plant life and animal life; the examination of the mysterious phenomena of the Aurora Borealis—these and many other interesting subjects of investigation have been as yet but incompletely dealt with. In the Polar regions, as Maury well remarked, “the icebergs are framed and glaciers launched; there the tides have their cradle, the whales their nursery; there the winds complete their circuit, and the currents of the sea their round, in the wonderful system of oceanic circulation; there the Aurora is lighted up, and the trembling needle brought to rest; and there, too, in the mazes of that mystic circle, terrestrial forces of occult power and of vast influence upon the well-being of man are continually at work. It is a circle of mysteries; and the desire to enter it, to explore its untrodden wastes and secret chambers, and to study its physical aspects, has grown into a longing. Noble daring has made Arctic ice and snow-clad seas classic ground.” _A MIGHTY SEA-WAVE._ On May 10th, 1876, a tremendous wave swept the Pacific Ocean from Peru northwards, westwards, and southwards, travelling at a rate many times greater than that of the swiftest express train. For reasons best known to themselves, writers in the newspapers have by almost common consent called this phenomenon a tidal-wave. But the tides had nothing to do with it. Unquestionably the wave resulted from the upheaval of the bed of the ocean in some part of that angle of the Pacific Ocean which is bounded by the shores of Peru and Chili. This region has long been celebrated for tremendous submarine and subterranean upheavals. The opinions of geologists and geographers have been divided as to the real origin of the disturbances by which at one time the land, at another time the sea, and at yet other times (oftener, in fact, than either of the others) both land and sea have been shaken as by some mighty imprisoned giant, struggling, like Prometheus, to cast from his limbs the mountain masses which hold them down. Some consider that the seat of the Vulcanian forces lies deep below that part of the chain of the Andes which lies at the apex of the angle just mentioned, and that the direction of their action varies according to the varying conditions under which the imprisoned gases find vent. Others consider that there are two if not several seats of subterranean activity. Yet others suppose that the real seat of disturbance lies beneath the ocean itself, a view which seems to find support in several phenomena of