ractically
in the proportion of 8, 7, 6, 5, 4, 3, allowing in each case for the
amount hidden by the projection of the cornice below; each order being
accurate as regards column, entablature, etc. It is of interest to
compare this with Ruskin's idea in his _Seven Lamps_, where he takes
the case of a plant called Alisma Plantago, in which the various
branches diminish in the proportion of 7, 6, 5, 4, 3, respectively,
and so carry out the same idea; on which Ruskin observes that
diminution in a building should be after the manner of Nature.

[Illustration 90: ARCADE OF THE CANCELLERIA]

It would be a profitless task to formulate exact rules of
architectural proportion based upon the laws of musical harmony. The
two arts are too different from each other for that, and moreover
the last appeal must always be to the eye, and not to a mathematical
formula, just as in music the last appeal is to the ear. Laws there
are, but they discover themselves to the artist as he proceeds, and
are for the most part incommunicable. Rules and formulae are useful and
valuable not as a substitute for inspiration, but as a guide: not as
wings, but as a tail. In this connection perhaps all that is necessary
for the architectural designer to bear in mind is that important
ratios of length and breadth, height and width, to be "musical" should
be expressed by quantitively small numbers, and that if possible they
should obey some simple law of numerical progression. From this basic
simplicity complexity will follow, but it will be an ordered and
harmonious complexity, like that of a tree, or of a symphony.

[Illustration 91: THE PALAZZO VERZI AT VERONA (LOWER PORTION ONLY).
A COMPOSITION FOUNDED ON THE EQUAL AND REGULAR DIVISION OF SPACE, AS
MUSIC IS FOUNDED ON THE EQUAL AND REGULAR DIVISION OF TIME.]

[Illustration 92: ARCHITECTURE AS RHYTHM. A DIVISION OF SPACE
CORRESPONDING TO 3/4 AND 4/4 TIME.]

In the same way that a musical composition implies the division of
time into equal and regular beats, so a work of architecture should
have for its basis some unit of space. This unit should be nowhere too
obvious and may be varied within certain limits, just as musical time
is retarded or accelerated. The underlying rhythm and symmetry will
thus give value and distinction to such variation. Vasari tells how
Brunelleschi. Bramante and Leonardo da Vinci used to work on paper
ruled in squares, describing it as a "truly ingenious thing, and of
great