to the mosaics of St. Mark's.

Now the main characteristics of an olive-tree are these. It has sharp
and slender leaves of a greyish green, nearly grey on the under surface,
and resembling, but somewhat smaller than, those of our common willow.
Its fruit, when ripe, is black and lustrous; but of course so small,
that, unless in great quantity, it is not conspicuous upon the tree. Its
trunk and branches are peculiarly fantastic in their twisting, showing
their fibres at every turn; and the trunk is often hollow, and even rent
into many divisions like separate stems, but the extremities are
exquisitely graceful, especially in the setting on of the leaves; and
the notable and characteristic effect of the tree in the distance is of
a rounded and soft mass or ball of downy foliage.

Sec. XV. Supposing a modern artist to address himself to the rendering
of this tree with his best skill: he will probably draw accurately the
twisting of the branches, but yet this will hardly distinguish the tree
from an oak: he will also render the color and intricacy of the foliage,
but this will only confuse the idea of an oak with that of a willow. The
fruit, and the peculiar grace of the leaves at the extremities, and the
fibrous structure of the stems, will all be too minute to be rendered
consistently with his artistical feeling of breadth, or with the amount
of labor which he considers it dexterous and legitimate to bestow upon
the work: but, above all, the rounded and monotonous form of the head of
the tree will be at variance with his ideas of "composition;" he will
assuredly disguise or break it, and the main points of the olive-tree
will all at last remain untold.

Sec. XVI. Now observe, the old Byzantine mosaicist begins his work at
enormous disadvantage. It is to be some one hundred and fifty feet above
the eye, in a dark cupola; executed not with free touches of the pencil,
but with square pieces of glass; not by his own hand, but by various
workmen under his superintendence; finally, not with a principal purpose
of drawing olive-trees, but mainly as a decoration of the cupola. There
is to be an olive-tree beside each apostle, and their stems are to be
the chief lines which divide the dome. He therefore at once gives up the
irregular twisting of the boughs hither and thither, but he will not
give up their fibres. Other trees have irregular and fantastic branches,
but the knitted cordage of fibres is the olive's own. Again, were h