ntation of his own (called Arabesque) to replace
it: this not being adapted for covering large surfaces, he concentrates
it on features of interest, and bars his surfaces with horizontal lines
of color, the expression of the level of the Desert. He retains the
dome, and adds the minaret. All is done with exquisite refinement.

Sec. XXVII. The changes effected by the Lombard are more curious still,
for they are in the anatomy of the building, more than its decoration.
The Lombard architecture represents, as I said, the whole of that of
the northern barbaric nations. And this I believe was, at first, an
imitation in wood of the Christian Roman churches or basilicas. Without
staying to examine the whole structure of a basilica, the reader will
easily understand thus much of it: that it had a nave and two aisles,
the nave much higher than the aisles; that the nave was separated from
the aisles by rows of shafts, which supported, above, large spaces of
flat or dead wall, rising above the aisles, and forming the upper part
of the nave, now called the clerestory, which had a gabled wooden roof.

These high dead walls were, in Roman work, built of stone; but in the
wooden work of the North, they must necessarily have been made of
horizontal boards or timbers attached to uprights on the top of the nave
pillars, which were themselves also of wood.[21] Now, these uprights
were necessarily thicker than the rest of the timbers, and formed
vertical square pilasters above the nave piers. As Christianity extended
and civilisation increased, these wooden structures were changed into
stone; but they were literally petrified, retaining the form which had
been made necessary by their being of wood. The upright pilaster above
the nave pier remains in the stone edifice, and is the first form of the
great distinctive feature of Northern architecture--the vaulting shaft.
In that form the Lombards brought it into Italy, in the seventh century,
and it remains to this day in St. Ambrogio of Milan, and St. Michele of
Pavia.

Sec. XXVIII. When the vaulting shaft was introduced in the clerestory
walls, additional members were added for its support to the nave piers.
Perhaps two or three pine trunks, used for a single pillar, gave the
first idea of the grouped shaft. Be that as it may, the arrangement of
the nave pier in the form of a cross accompanies the superimposition of
the vaulting shaft; together with corresponding grouping of minor shafts
i