These volumes, as they now appear, will probably be perused by two distinct classes . To the first, the really scientific reader, the Author will venture, though perhaps at the risk of some undeserved suspicion of egotism or vanity, to commend the subject and the method which they evolve, as pregnant with the power of future knowledge, of the cosmical conditions of the interior of our own and of other planets; that will be hereafter recognized as having first shown the way to any true intelligence from the viewless and unmeasured miles of matter beneath our feet; and that will ere long give us up the key to the hitherto undeciphered enigma of vulcanicity.
To the general reader, earthquake narratives have long shared in some degree, the charm that belongs to tales of shipwreck, of battle, or wild adventure, and "perilous hair-breadth 'scapes'" amidst natural phenomena the most tremendous: something of this he here will find; and though sobered to a reality not always found in earthquake stories, the events by which such multitudes perished, in which so many cities were overthrown, will be found by him who shall have even generally understood the principles here unfolded, to yield more intelligent pleasure, than the exaggerated and often fabulous phantasmagoria, of the older earthquake narratives, in the maze of which he wandered without any rational clue.
He will here trace with interest the successive steps by which finally the depth of the focus, whence the impulse that produced the earthquake has been for the
