hich is in a horizontal direction. Against
strains of this description, where the movements have an amplitude of
more than a few inches, no ordinary masonry edifice can be made
perfectly safe; the only tolerable security is attained where the
building is of well-framed timber, which by its elasticity permits a
good deal of motion without destructive consequences. Even such
buildings, however, those of the strongest type, may be ruined by the
greater earthquakes. Thus, in the Mississippi Valley earthquake of
1811, the log huts of the frontiersmen, which are about as strong as
any buildings can be made, were shaken to pieces by the sharp and
reiterated shocks.

It is by no means surprising to find that the style of architecture
adopted in earthquake countries differs from that which is developed
in regions where the earth is firm-set. The people generally learn
that where their buildings must meet the trials of earthquakes they
have to be low and strong, framed in the manner of fortifications, to
withstand the assault of this enemy. We observe that Gothic
architecture, where a great weight of masonry is carried upon slender
columns and walls divided by tall windows, though it became the
dominant style in the relatively stable lands of northern Europe,
never gained a firm foothold in those regions about the Mediterranean
which are frequently visited by severe convulsions of the earth. There
the Grecian or the Romanesque styles, which are of a much more massive
type, retain their places and are the fashions to the present day.
Even this manner of building, though affording a certain security
against slight tremblings, is not safe in the greater shocks. Again
and again large areas in southern Italy have been almost swept of
their buildings by the destructive movements which occur in that
realm. The only people who have systematically adapted their
architectural methods to earthquake strains are the Japanese, who in
certain districts where such risks are to be encountered construct
their dwellings of wood, and place them upon rollers, so that they may
readily move to and fro as the shock passes beneath them. In a measure
the people of San Francisco have also provided against this danger by
avoiding dangerous weights in the upper parts of their buildings, as
well as the excessive height to which these structures are lifted in
some of our American towns.

Earthquakes of sensible energy appear to be limited to particular
part