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hrow every port inland, or so far lowered as to submerge the richest and most populous regions. No doubt, the relations of sea and land have been much as they are during historical time; but it is at the same time past all doubt, that the last great geological event, in respect of most countries known, was a submergence which produced the marine alluvial deposits; and when we find that Scandinavia is slowly but steadily rising in some parts at this moment, and that a thousand miles of the west coast of South America rose four feet in a single night only thirty years ago, we cannot feel quite assured, that the agencies which produced that submergence, and the subsequent re-emergence, are at an end. We likewise forgot, in these cool districts of the earth, that we are not quite beyond the hazard of subterranean fire. There are numberless extinct volcanoes in both Britain and France; there are some on the banks of the Rhine; indeed, they are thick-sown everywhere. Now, an extinct volcano is not quite so safe a neighbour as many may suppose. Vesuvius was an extinct volcano from time immemorial till the year 63, when it suddenly broke out again, and soon after destroyed Pompeii and Herculaneum; since which time it has never again subsided into entire inactivity. Suppose Arthur's Seat, which is 'within a mile of Edinburgh town,' were to recommence business in like manner, we should like to know at how many years' purchase house property in that beautiful New Town would be selling next day. Yet what is there about an old volcano here more than an old volcano in Italy, to give assurance that its means of annoyance and destruction are absolutely extinguished?
There is, however, in the showings of science, a more serious danger than any of these. Comets were once regarded as most terrific objects, but only in a superstitious way, perplexing nations with fear of change, and shaking pestilence from their horrid hair. During an intermediate enlightened time, these notions passed away; and we have even come to think, th