4. It will be desirable also that you clearly learn the material
relations, governing spiritual ones,--as of the Alps to their clouds,
so of the plains to their rivers. And of these rivers, chiefly note the
relation to each other, first, of the Adige and Po; then of the Arno
and Tiber. For the Adige, representing among the rivers and fountains
of waters the channel of Imperial, as the Tiber of the Papal power, and
the strength of the Coronet being founded on the white peaks that look
down upon Hapsburg and Hohenzollern, as that of the Scarlet Cap in the
marsh of the Campagna, "quo tenuis in sicco aqua destituisset," the
study of the policies and arts of the cities founded in the two great
valleys of Lombardy and Tuscany, so far as they were affected by their
bias to the Emperor, or the Church, will arrange itself in your minds
at once in a symmetry as clear as it will be, in our future work,
secure and suggestive.

5. "Tenuis, in sicco." How literally the words apply, as to the native
streams, so to the early states or establishings of the great cities of
the world. And you will find that the policy of the Coronet, with its
tower-building; the policy of the Hood, with its dome-building; and the
policy of the bare brow, with its cot-building,--the three main
associations of human energy to which we owe the architecture of our
earth, (in contradistinction to the dens and caves of it,)--are
curiously and eternally governed by mental laws, corresponding to the
physical ones which are ordained for the rocks, the clouds, and the
streams.

The tower, which many of you so well remember the daily sight of, in
your youth, above the "winding shore" of Thames,--the tower upon the
hill of London; the dome which still rises above its foul and